Eunseo Kim; Su-Hyun Jo

doi:10.4196/kjpp.25.098

Journal List > Korean J Physiol Pharmacol > v.29(5) > 1516092499

Go to TopGo to Top Go to BottomGo to Bottom

TOOLS

Kim and Jo: Effects of β-adrenoceptor antagonist and 5-HT1A and 5-HT1B receptor antagonist alprenolol on human Kv1.3 currents

Original Article

Korean J. Physiol. Pharmacol. 2025;29(5):649-658.

Published online: 1 September 2025

DOI: https://doi.org/10.4196/kjpp.25.098

Effects of β-adrenoceptor antagonist and 5-HT_1A and 5-HT_1B receptor antagonist alprenolol on human Kv1.3 currents

Eunseo Kim, Su-Hyun Jo^*

Department of Physiology, Institute of Bioscience and Biotechnology, Kangwon National University College of Medicine, Chuncheon 24341, Korea

^*Correspondence Su-Hyun Jo, E-mail: suhyunjo@kangwon.ac.kr

Contributed by:

Author contributions: E.K. performed the voltage-clamp experiments, analyzed the data, and wrote the first draft of the manuscript. S.H.J. supervised, coordinated the study, and edited into final manuscript.

Received 27 March 2025 Revised 26 May 2025 Accepted 5 June 2025

(open-access):

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Alprenolol is a nonselective β-adrenoceptor antagonist used in treating cardiovascular diseases by stabilizing elevated heart rates and myocardial contractility through the inhibition of sympathetic nerve transmissions alongside its role as an antagonist of 5-HT_1A and 5-HT_1B receptors. This study aimed to examine whether alprenolol can affect human Kv1.3 channel (hKv1.3) currents, which contribute to the proliferation and activation of T lymphocytes by regulating the driving force of Ca²⁺ influx. We investigated the acute effects of alprenolol on hKv1.3 channel currents using two-microelectrode voltage clamp recordings in Xenopus oocytes. Alprenolol exhibited concentration-dependent biphasic effects on hKv1.3 currents: it increased the current amplitudes at 1–100 µM but decreased them at 300–1,000 µM during a +50 mV depolarization step. A significant difference was found in alprenolol’s effects on the peak and steady-state currents after 6 min of treatment with 10 µM, 50 µM, and 100 µM and 12 min of treatment with 10 µM and 50 µM. Furthermore, alprenolol affected the time constants of intrinsic inactivation and ultrarapid activation. However, no significant changes in V_1/2 and k value were found for steady-state activation and inactivation curves, except for the k value between 50 µM and 1,000 µM of the inactivation curve. At 1,000 µM, alprenolol suppressed hKv1.3 currents more rapidly during 5 sec inter-stimulus intervals compared to 15 sec intervals, indicating use-dependent blockade. Therefore, the effects of alprenolol on the biphasic and various biophysical properties of hKv1.3 channels could cause drug concentration-dependent changes in immune function.

Keywords: Adrenoceptor, Alprenolol, Kv1.3 potassium channel, T lymphocytes, 5-HT_1A and 5-HT_1B receptor antagonist

INTRODUCTION

Kv1.3 channels belong to the shaker subfamily of voltage-dependent K⁺ channels which are encoded by the KCNA3 gene [1,2]. Kv1.3 is abundantly located in lymphocytes, vascular smooth muscle cells (VSMCs), central nervous system, and osteoclasts and is an important contributor to cell proliferation [3,4]. Among those various approaches for Kv1.3 channel studies, many studies have been linked Kv1.3 channels to T lymphocytes since the early 1980s [5 -8]. As a modulator of immune function, Kv1.3 induces Kv1.3-mediated T-lymphocyte proliferation and activation of human CD4+ and CD8+ effector memory T cells by setting the driving force of Ca²⁺ influx as the membrane potential model [9]. Therefore, Kv1.3 channels are being considered as a promising therapeutic target for immunosuppressive diseases such as autoimmune diseases by regulating their activation [10].

Alprenolol is a nonselective β-adrenoceptor antagonist in the cardiovascular system and an antagonist of 5-HT_1A and 5-HT_1B receptors [11 -13]. As a β-adrenoceptor antagonist, alprenolol is used as an antihypertensive, antianginal, and antiarrhythmic agent by inhibiting sympathetic nerve activation from binding of catecholamines such as epinephrine and norepinephrine, resulting decrease of heart contractility and stabilizes artery spasms [14]. Theoretically, alprenolol may affect cancer progression across various cancer types as an antagonist of 5-HT_1A and 5-HT_1B receptors by blocking 5-HT-induced tumor growth in various types of human tumor, such as prostate, bladder, small cell lung, colorectal, and cholangiocarcinoma; however, alprenolol-specific oncology studies are not conducted enough [15,16]. While the general effects of alprenolol on Kv1.3 channels have not been reported; the case report of alprenolol-induced thrombocytopenia was demonstrated that it was mediated through an immunological mechanism [17]. Thus, the physiological interaction between Kv1.3 channels and alprenolol is expected to affect immune functions by regulating T-lymphocyte proliferation and its current activation.

In this study, we aimed to examine the effects of alprenolol on human Kv1.3 (hKv1.3) channel currents through voltage-clamping assays in Xenopus oocytes that are well-known effective cellular model for investigating individual channel physiology. Moreover, alprenolol-induced changes in the hKv1.3 channel current amplitude and biophysical properties were investigated, and the potential implications of the physiological effects of alprenolol on the immune, neuronal, and circulatory systems were discussed.

METHODS

hKv1.3 channel expression in Xenopus oocytes

cRNA encoding the hKv1.3 channel (GenBank accession no. BC035059.1) was synthesized using Message Machine T7 Kits (Ambion) via in vitro transcription and stored in sterile nuclease-free water at −80°C. Female Xenopus laevis (Nasco or the Korean Xenopus Resource Center for Research) were anesthetized using 0.17% tricaine methanesulfonate (Sigma), and their oocytes (at stage V and VI) were surgically collected using fine forceps from the theca and follicle layers. All procedures associated with the use of Xenopus were performed in accordance with the Research Guidelines of Kangwon National University IACUC and no separate approval was required. Injections of 20 nl cRNA (0.4 μg/μl) into the oocytes were performed 2 days after their isolation. After cRNA injections, oocytes were maintained at 17°C in modified Barth’s Solution containing 88 mM NaCl, 1 mM KCl, 0.4 mM CaCl, 0.33 mM Ca(NO₃)₂, 1 mM MgSO₄, 2.4 mM NaHCO₃, 10 mM HEPES (pH 7.4), and 50 µg/ml gentamicin sulfate. Currents were measured 3–6 days after injection.

Conditions of voltage-clamp recording using oocytes

The experimental bath chamber was continuously perfused for 3 min with Ringer’s solution containing 96 mM NaCl, 2 mM KCl, 1.8 mM CaCl₂, 1 mM MgCl₂, and 10 mM HEPES (pH 7.4) to replace the existing solution and deliver new Ringer’s solution to the oocytes. Following solution exchange at room temperature (20°C–23°C), currents were recorded at 6 and 12 min using an OC-725C two-microelectrode voltage-clamp amplifier (Warner Instruments). In addition, 3 M KCl was used to fill the voltage-recording and current-passing electrodes, which had resistances of 2–4 MΩ and 2.0–2.5 MΩ, respectively. Digidata 1440 and pCLAMP 10 software (Molecular Devices) were used to control the stimulation and extract data. A stock solution of alprenolol (Fig. 1) was prepared in distilled water and added to the external solution at defined concentrations immediately before each experiment. All reagents were obtained from Sigma-Aldrich.

Data analysis

For data acquisition and analysis, we used Origin 8.0 software (OriginLab Corporation). Data related to the concentration-dependent current inhibition were analyzed using the Hill equation (1):

(1)

y = 1 / [1 + (I C_{50} / {[D]}^{n})],

where IC50 is the drug concentration at which inhibition of currents was half-maximal and [D] is the concentration of alprenolol. Each tail current was normalized to +40 mV to obtain data for the steady-state activation curves. Data were also fitted to Boltzmann equation (2) to obtain steady-state activation curves:

(2)

y = 1 / {1 + \exp [- (V - V_{1 / 2}) / k]},

where V denotes the test potential, V_1/2 denotes the potential for half-activation (the voltage at which the conductance was half-activated), and k is the slope factor. Each tail current was normalized to the tail current recorded at −80 mV to obtain steady-state inactivation data, which were subsequently fitted to another Boltzmann equation (3):

(3)

y = 1 / [1 + \exp (V - V_{1 / 2}) / k],

where V, V_1/2, and k denote the same parameters defined in equation (2).

All data are presented as means ± standard error of the mean (SEM). Paired Student’s t-tests or analysis of variance (ANOVA) were used to test for differences in mean values in the data. Statistical significance was determined using one-way ANOVA followed by Tukey’s post-hoc test. Differences were considered significant at p < 0.05.

RESULTS

Effects of alprenolol on hKv1.3 channel currents

We examined whether alprenolol could change the currents of hKv1.3 channels using voltage-clamp recording methods with and without treatments of 1–1,000 μM alprenolol for 6 and 12 min (Fig. 2). The result showed dose-dependently increased hKv1.3 channel currents at 1–100 μM and decreased currents at 300 and 1,000 μM of alprenolol treatment (Fig. 2). Alprenolol treatment at 50 μM for 6 min potentiated the peak currents at +50 mV by 15.2% ± 1.0% (n = 3–12; Fig. 2B) and steady-state currents at +50 mV by 32.3% ± 3.7% (n = 4–10; Fig. 2C). Further 12 min with the same concentration of alprenolol manifested increased peak currents at +50 mV by 21.8% ± 2.8% (n = 4–8; Fig. 2D) and steady-state currents at +50 mV by 50.4% ± 8.1% (n = 3–15; Fig. 2E). However, 6 min treatment with 1,000 μM alprenolol treatment not only suppressed the peak currents at +50 mV by 44.0% ± 6.7% (n = 3–12; Fig. 2B) and steady-state currents at +50 mV by 22.4% ± 4.0% (n = 4–10; Fig. 2C) after 6 min, but also 12 min treatment with 1,000 μM alprenolol showed decreased peak currents at +50 mV by 43.7% ± 7.6% (n = 4–8; Fig. 2D) and steady-state currents at +50 mV by 35.5% ± 11.5% (n = 3–15; Fig. 2E). These results indicated an acute biphasic effect of alprenolol on hKv1.3 channels depending on its concentrations.

Concentration- and state-dependent changes of hKv1.3 channel currents induced by alprenolol

Continuously with the overview of alprenolol-induced current changes shown in Fig. 2, further assessments were conducted to characterize impacts of alprenolol treatments on hKv1.3 channel current. The result manifested the dose-dependent changes in the hKv1.3 current at +50 mV (Fig. 3). Fig. 3A and 3B show the rate of current change induced by alprenolol at +50 mV after 6 and 12 min, indicating the dose-dependent biphasic effect of alprenolol on hKv1.3 channel currents. A significant difference was observed in alprenolol’s effects on the peak and steady-state currents after 6 min of treatment with 10 μM, 50 μM, and 100 μM and 12 min of treatment with 10 μM and 50 μM (n = 3–12, p < 0.05). Moreover, to efficiently clarify its dose-dependency to the channel current activation, the concentration-dependent effects of 0.3–50 μM alprenolol for 6 and 12 min were monitored (Fig. 3C, D). The result showed elevated peak currents of hKv1.3 channels 6 min after the administration in a concentration-dependent manner, which reached the maximum at 50 μM by 27.9% ± 4.9%, alongside showing increased steady-state currents by 32.3% ± 3.8% (n = 3–12; Fig. 3C). Furthermore, the 12 min treatment of alprenolol induced similar dose-dependent increases in the peak current by 21.8% ± 2.8% and the steady-state current by 50.9% ± 8.1% at 50 μM (n = 4–5; Fig. 3D) beside the greater effects on the steady-state current than those on the peak current at 10–50 μM (n = 3–12, p < 0.05; Fig. 3C, D). As conclusion, the results clearly asserted that the alprenolol-induced changes of hKv1.3 channel currents were dosage- and state-dependent.

Lack of alprenolol-induced voltage-dependent effects on hKv1.3 channel currents

To investigate whether alprenolol exhibits voltage-dependency to hKv1.3 channels, alprenolol-induced current changes in hKv1.3 channel were compared at each test voltage. The assessment was done by normalizing the current measured at each test voltage against the control current measured at the same voltage (Fig. 4). During the depolarization of the test voltage from −30 to +50 mV for 6 and 12 min, alprenolol did not change the peak or steady-state currents of hKv1.3 channels at either 50 μM or 1,000 μM (n = 3–8, p > 0.05; Fig. 4), indicating a lack of voltage dependence. However, alprenolol-induced current change showed a significant difference between steady-state and peak currents after treatments with either 50 μM for 6 and 12 min or 1,000 μM for 12 min (n = 3–8, p < 0.05; Fig. 4A, C, D). In addition, a stronger potentiating effect of 50 μM alprenolol (Fig. 4A, C) or inhibiting effects of 1,000 μM alprenolol (Fig. 4A, C) on the steady-state current rather than on the peak current of hKv1.3 channels occurred after 12 min of treatment compared with that after 6 min of treatment, indicating the time-dependent effect of alprenolol (n = 3–8, p < 0.05; Fig. 4).

Effects of alprenolol on the activation and inactivation time constants of hKv1.3 channels

The effect of alprenolol on the hKv1.3 channel activation and inactivation time constants were estimated by fitting the current trace using an exponential function (Fig. 5). Alprenolol showed a significant increase in activation time constants at 10 μM and 50 μM and a decrease in the time constants at 1,000 μM (n = 4–8, p > 0.05; Fig. 5A, B), indicating alprenolol’s different effects on the activation process depending on the drug concentration. In addition, alprenolol significantly reduced the time constants of inactivation in a dose-dependent manner with 50, and 1,000 μM (n = 5–8, p < 0.05; Fig. 5C, D). These results asserted that the similar effects on the intrinsic inactivation of hKv1.3 channels were induced by alprenolol treatments in a concentration-dependent manner, while manifesting the opposing effects on ultrarapid activation depending on concentration.

Alprenolol did not significantly affect the steady-state activation and inactivation of hKv1.3 channels

To examine whether alprenolol could influence the activation or inactivation kinetics of hKv1.3 channels, two-pulse protocols were used as indicated in Figs. 6A and 7A. Steady-state activation and inactivation curves were obtained by fitting the normalized tail currents with Boltzmann equations (Figs. 6B and 7B). The control values of V_1/2 and the slope (k) of the activation curve were −24.5 ± 4.1 mV and 18.5 ± 3.7, respectively (n = 6, Fig. 6B). The V_1/2 and k of treatment with 50 and 1,000 μM alprenolol were −24.1 ± 4.6 mV and 18.1 ± 4.2 and −27.3 ± 4.4 mV and 18.9 ± 3.8, respectively (n = 3–4, p > 0.05; Fig. 6B). For the steady-state inactivation curve, the control values of V_1/2 and k were −32.4 ± 1.2 mV and 3.7 ± 0.5, respectively (n = 8; Fig. 7B). After exposure to 50 μM and 1,000 μM alprenolol, the corresponding values were −32.8 ± 0.7 mV and 3.4 ± 0.3 and −30.9 ± 1.1 mV and 3.8 ± 0.5, respectively (n = 6, p > 0.05; Fig. 7B). The results suggested that alprenolol did not change the voltage dependence of either the activation or inactivation curve and the degree of slope of the activation curve compared with the control while observing the significant slope difference of the inactivation curves at 50 μM and 1,000 μM of alprenolol treatment (n = 6, p < 0.05; Fig. 7B).

Use-dependent blockade of hKv1.3 channels by alprenolol

Finally, we aimed to investigate whether the alprenolol-induced suppression of hKv1.3 is exhibiting use-dependency by applying 0.2 sec depolarizing steps to +60 mV at 5 and 15 sec intervals (Fig. 8). Control experiments were performed to determine the use-dependent effect on hKv1.3 currents in oocytes without alprenolol (data not shown). Subsequently, we subtracted the values obtained in the presence of alprenolol from the control values recorded in the absence of alprenolol in the perfusion solution. The blockade of the hKv1.3 channel peak current by 1,000 μM alprenolol was drastic and reached saturation levels of 93.8% ± 0.5% and 84.2% ± 2.9% at stimulation rates of 5 sec and 15 sec intervals, respectively (n = 4–5, Fig. 8A), and the inhibition of the steady-state current reached saturation levels of 94.7% ± 0.4% and 86.1% ± 2.4% at the same stimulation rates (n = 4–5, Fig. 8B). Alprenolol inhibited hKv1.3 channels more rapidly as the frequency of stimulation increased. Fig. 8C presents the results from Fig. 8A as a function of the number of test pulses. When the same number of test pulses was compared, higher stimulation frequencies induced a stronger blockade by 1,000 μM alprenolol. These characteristics were consistent with alprenolol-induced suppression of steady-state current (Fig. 8B, D). This finding indicates a preference for higher stimulation frequencies to achieve the blocking effect of alprenolol on hKv1.3 channels, even when the drug is administered for the same duration.

DISCUSSION

hKv1.3 channels are voltage-gated potassium channels located in the plasma membrane which are known to contribute regulating repolarization of the membrane action potential and calcium signaling. Since the early 1980s, Kv1.3 channels have been studied as a modulator of cell proliferation, particularly to T lymphocytes [7,9]. We found that alprenolol, widely known as a nonselective β-adrenoceptor antagonist for heart disease treatments and a 5-HT_1A and 5-HT_1B receptor antagonist, influenced hKv1.3 channels in the opposite directions depending on concentration. Alprenolol increased hKv1.3 channel currents at comparably low concentrations from 1 to 100 μM and suppressed currents at comparably high concentrations from 300 to 1,000 μM (Fig. 2). The channel current-increasing effect of alprenolol was concentration-dependent, and the enhancing effect on steady-state currents was greater than that on the peak current with the same test voltage at 10 and 50 μM (Fig. 3). Furthermore, 10, 50, and 1,000 μM alprenolol affected the activation and inactivation time courses (Fig. 6); however, 50 and 1,000 μM did not alter the steady-state activation and inactivation curves (Figs. 6 and 7). Moreover, 1,000 μM alprenolol demonstrated use-dependent suppression of hKv1.3 channel currents, manifesting more rapid channel blocking at higher concentrations (Fig. 8). In the present study, alprenolol affected hKv1.3 steady-state currents more than the peak currents in the +50 mV membrane voltage range at relatively low concentrations (Fig. 3). Furthermore, alprenolol blocked hKv1.3 channels faster when the stimulation frequency increased (Fig. 8) and accelerated channel inactivation (Fig. 5). Considering these results, alprenolol may function as an open-channel effector that influences hKv1.3 channels without altering the voltage dependence of either activation or inactivation gating (Figs. 6 and 7).

Based on pharmacokinetic studies, steady-state plasma concentrations of alprenolol for the treatment of heart disease were reported to range from 6 to 1,700 nM in treated patients [18,19]. However, Xenopus oocyte expression system which has utilized in our study, is well known effective cellular model for ion channel physiology studies exhibiting its properties such as the vitelline envelope and egg yolk of oocytes, requiring 10–100 times higher concentrations of drug to influence K⁺ channel current expressed in oocytes [20 -22]. In addition to properties of the Xenopus oocyte expression system, alprenolol’s high lipophilicity and its large apparent distribution volume (~2.99 L/kg) could cause comparably higher concentration in certain tissues or subcellular domains than plasma levels [23]. For instance, local concentrations in lipid-rich tissues or specific subcellular microdomains may reach low micromolar concentrations despite rapid systemic clearance kinetics in human due to the drug accumulation and this phenomenon has been observed in a study comparing accumulated alprenolol’s concentration in organs of rat [23,24]. Therefore, the effects of different doses of alprenolol observed in this study, ranging from 1 to 1,000 μM (Fig. 2) to hKv1.3 channel current, can be related to the alprenolol’s therapeutic plasma concentration of ~1.7 μM as mentioned above [18].

Kv1.3 channels are located in various tissues and cells: immune, central nervous system, and VSMCs. Among these tissues and cells, Kv1.3 channels are abundantly expressed in T cells and affect proliferation through the regulation of IL-2 production by membrane hyperpolarization mechanism by controlling K⁺ efflux [9]. Furthermore, Kv1.3 channels can influence the immune system by augmenting the channel expression in macrophages activated in response to inflammation [25]. In the central nervous system and VSMCs, glial cell proliferation and basal tone maintenance can be regulated through physiological and pathological mechanisms of Kv1.3 channel function [9,26,27].

Several studies with other β-adrenoceptor antagonists have focused on potential immunomodulation based on the accumulated evidence of the pathogenic role of the adaptive immune system in chronic heart failure [28]. Carvedilol therapy showed immunomodulatory benefits among other alternative β-adrenoceptor antagonists by regulating Kv1.3 channel currents in HEK293 cells [29,30]. Furthermore, the blockade of β-adrenergic receptors by propranolol improved CD8+ T cell priming [31]. The present study showed biphasic effects of alprenolol on hKv1.3, different characteristics from other β-adrenoceptor blockers, which showed their inhibitory effects on Kv channels through direct pore block or via β-adrenergic signaling pathways that modulate channel phosphorylation [32,33]. However, there has been the report showing the biphasic effects on K⁺ channel; B subunit of beta-bungarotoxin and morphine in a pathological condition have shown the biphasic effects on Kv channels and K_ATP channel, respectively [34,35]. Considering that membrane hyperpolarization by hKv1.3 activation contributes to T-lymphocyte proliferation by activating Ca²⁺-dependent transcription factors [5,6,8], our results indicated that alprenolol might affect hKv1.3 currents in the human immune system depending on its concentration and influence IL-2 production mechanism [9,36] differently than the other β-adrenoceptor blockers.

In addition, alprenolol exerted acute, concentration-dependent effects on hKv1.3 channels, likely through mechanisms independent of its known antagonism at β-adrenergic and 5-HT_1A/_1B receptors due to our experiment setups using Xenopus oocytes excluding adrenergic and 5-HT regulatory systems. Our results showed that alprenolol at lower concentrations (1–100 μM) enhanced hKv1.3 currents without a significant shift in the half-inactivation voltage (V_1/2), but with a change in the slope factor (k) of the steady-state inactivation curve (Fig. 7). This suggests a potential modulation of channel gating dynamics, such as allosteric interactions that stabilize the open state or delay inactivation. Despite having no direct evidence of alprenolol binding to channel subunits themselves, it is plausible that alprenolol might interact with the channel at sub-blocking doses in a way that stabilizes the open state or slows the transition to inactivation, thereby enhancing current. This could occur via allosteric modulation possibly by binding to a site distinct from the pore, subtly altering channel conformation to favor opening or delay inactivation supported by such reports. Recently, Liang et al. [37] have shown that an imidazolidinedione derivative, a highly selective positive allosteric modulator of Kv3.1 and Kv3.2 channels, involves positive cooperativity and preferential stabilization of the open state. The FTL motif (F57-T58-L59) of KCNE could bind at a cleft between the voltage-sensing and pore domains of KCNQ1 channel, affecting the channel gate by an allosteric mechanism, resulting in slow activation [38]. Also, there are reports showing the impact of allosterically-coupled conformational change to K⁺ channel inactivation process kinetic models including change of slope factor (k) [39,40]. Further structural analyses between alprenolol and Kv1.3 channel would be needed to support our hypothesis.

In conclusion, the results of this study showed the biphasic concentration-, time- and frequency-dependent effects of alprenolol on hKv1.3 channel currents. Alprenolol-induced acceleration of the inactivation process and the voltage-dependent decrease in hKv1.3 channel steady-state currents indicated that open-channel inhibition was preferred over closed-state suppression. The contrasting effects depending on concentration of alprenolol on hKv1.3 channels may affect the physiological functions of the human immune, nervous, and circulatory systems. Further studies through β-adrenoceptor on the binding between adrenergic β-adrenoceptor antagonists and hKv1.3 channels are needed to discover the molecular mechanism based on the pharmacological modulation of the immune system by β-adrenoceptor antagonists.

ACKNOWLEDGEMENTS

The authors wish to thank Prof. Han Choe (Department of Physiology, Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Korea) for providing the human Kv1.3 gene.

Notes

FUNDING

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. RS-2023-00250981).

CONFLICTS OF INTEREST

The authors declare no conflicts of interest.

REFERENCES

1. Ader C, Schneider R, Hornig S, Velisetty P, Wilson EM, Lange A, Giller K, Ohmert I, Martin-Eauclaire MF, Trauner D, Becker S, Pongs O, Baldus M. 2008; A structural link between inactivation and block of a K+ channel. Nat Struct Mol Biol. 15:605–612. DOI: 10.1038/nsmb.1430. PMID: 18488040.

2. Swanson R, Marshall J, Smith JS, Williams JB, Boyle MB, Folander K, Luneau CJ, Antanavage J, Oliva C, Buhrow SA, et al. 1990; Cloning and expression of cDNA and genomic clones encoding three delayed rectifier potassium channels in rat brain. Neuron. 4:929–939. DOI: 10.1016/0896-6273(90)90146-7. PMID: 2361015.

3. Cheong A, Li J, Sukumar P, Kumar B, Zeng F, Riches K, Munsch C, Wood IC, Porter KE, Beech DJ. 2011; Potent suppression of vascular smooth muscle cell migration and human neointimal hyperplasia by KV1.3 channel blockers. Cardiovasc Res. 89:282–289. DOI: 10.1093/cvr/cvq305. PMID: 20884640. PMCID: PMC3020133.

4. Gutman GA, Chandy KG, Grissmer S, Lazdunski M, McKinnon D, Pardo LA, Robertson GA, Rudy B, Sanguinetti MC, Stühmer W, Wang X. 2005; International Union of Pharmacology. LIII. Nomenclature and molecular relationships of voltage-gated potassium channels. Pharmacol Rev. 57:473–508. DOI: 10.1124/pr.57.4.10. PMID: 16382104.

5. Cahalan MD, Chandy KG. 1997; Ion channels in the immune system as targets for immunosuppression. Curr Opin Biotechnol. 8:749–756. DOI: 10.1016/S0958-1669(97)80130-9. PMID: 9425667.

6. Chandy KG, Wulff H, Beeton C, Pennington M, Gutman GA, Cahalan MD. 2004; K+ channels as targets for specific immunomodulation. Trends Pharmacol Sci. 25:280–289. DOI: 10.1016/j.tips.2004.03.010. PMID: 15120495. PMCID: PMC2749963.

7. DeCoursey TE, Chandy KG, Gupta S, Cahalan MD. 1984; Voltage-gated K+ channels in human T lymphocytes: a role in mitogenesis? Nature. 307:465–468. DOI: 10.1038/307465a0. PMID: 6320007.

8. Feske S, Giltnane J, Dolmetsch R, Staudt LM, Rao A. 2001; Gene regulation mediated by calcium signals in T lymphocytes. Nat Immunol. 2:316–324. Erratum in: Nat Immunol. 2008;9:328-329. DOI: 10.1038/ni0308-328.

9. Pérez-García MT, Cidad P, López-López JR. 2018; The secret life of ion channels: Kv1.3 potassium channels and proliferation. Am J Physiol Cell Physiol. 314:C27–C42. DOI: 10.1152/ajpcell.00136.2017. PMID: 28931540.

10. Lam J, Wulff H. 2011; The lymphocyte potassium channels Kv1.3 and KCa3.1 as targets for immunosuppression. Drug Dev Res. 72:573–584. DOI: 10.1002/ddr.20467. PMID: 22241939. PMCID: PMC3253536.

11. de Peuter OR, Lussana F, Kamphuisen PW. 2007; Abstract 3215: effects of selective and non-selective beta-blockers on cardiovascular risk in patients with heart failure or acute coronary syndrome: a meta-analysis. Circulation. 116:284–294. DOI: 10.1161/circ.116.suppl_16.II_723-a.

12. Jackson CD, Fishbein L. 1986; A toxicological review of beta-adrenergic blockers. Fundam Appl Toxicol. 6:395–422. DOI: 10.1016/0272-0590(86)90214-9. PMID: 2870945.

13. Smith CF, Bennett RT. 1990; Characterization of the inhibitory 5-HT receptor in the rat vas deferens. Arch Int Pharmacodyn Ther. 308:76–85.

14. Louis WJ, Taylor H, McNeil JJ, Jarrott B, Rand MJ. 1982; Clinical pharmacology of adrenergic-adrenoreceptor-blocking drugs. Am Heart J. 104:407–412. DOI: 10.1016/0002-8703(82)90130-2. PMID: 6125097.

15. Corvino A, Fiorino F, Severino B, Saccone I, Frecentese F, Perissutti E, Di Vaio P, Santagada V, Caliendo G, Magli E. 2018; The role of 5-HT_1A receptor in cancer as a new opportunity in medicinal chemistry. Curr Med Chem. 25:3214–3227. DOI: 10.2174/0929867325666180209141650. PMID: 29424302.

16. Yap A, Lopez-Olivo MA, Dubowitz J, Pratt G, Hiller J, Gottumukkala V, Sloan E, Riedel B, Schier R. 2018; Effect of beta-blockers on cancer recurrence and survival: a meta-analysis of epidemiological and perioperative studies. Br J Anaesth. 121:45–57. DOI: 10.1016/j.bja.2018.03.024. PMID: 29935594.

17. Magnusson B, Rödjer S. 1980; Alprenolol-induced thrombocytopenia. Acta Med Scand. 207:231–233. DOI: 10.1111/j.0954-6820.1980.tb09711.x. PMID: 7368989.

18. Rawlins MD, Collste P, Frisk-Holmberg M, Lind M, Ostman J, Sjöqvist F. 1974; Steady-state plasma concentrations of alprenolol in man. Eur J Clin Pharmacol. 7:353–356. DOI: 10.1007/BF00558205. PMID: 4419005.

19. Collste P, Haglund K, Frisk-Holmberg M, Rawlins MD. 1976; Pharmacokinetics and pharmacodynamics of alprenolol in the treatment of hypertension. I. Relationship between plasma concentration and adrenergic beta-receptor blockade. Eur J Clin Pharmacol. 10:85–88. DOI: 10.1007/BF00609464. PMID: 9292.

20. Borchard U. 1998; Pharmacological properties of beta-adrenoceptor blocking drugs. J Clin Basic Cardiol. 1:5–9.

21. Jo SH, Hong HK, Chong SH, Choe H. 2008; Protriptyline block of the human ether-à-go-go-related gene (HERG) K+ channel. Life Sci. 82:331–340. DOI: 10.1016/j.lfs.2007.12.004. PMID: 18191158.

22. Lee HM, Hahn SJ, Choi BH. 2016; Blockade of Kv1.5 by paroxetine, an antidepressant drug. Korean J Physiol Pharmacol. 20:75–82. DOI: 10.4196/kjpp.2016.20.1.75. PMID: 26807026. PMCID: PMC4722194.

23. Bodin NO, Borg KO, Johansson R, Obianwu H, Svensson R. 1974; Absorption, distribution and excretion of alprenolol in man, dog and rat. Acta Pharmacol Toxicol (Copenh). 35:261–269. DOI: 10.1111/j.1600-0773.1974.tb00745.x. PMID: 4479578.

24. Johnsson G, Sjögren J, Sölvell L. 1971; Beta-blocking effect and serum levels of alprenolol in man after administration of ordinary and sustained release tablets. Eur J Clin Pharmacol. 3:74–81. DOI: 10.1007/BF00619298.

25. Vicente R, Escalada A, Coma M, Fuster G, Sánchez-Tilló E, López-Iglesias C, Soler C, Solsona C, Celada A, Felipe A. 2003; Differential voltage-dependent K+ channel responses during proliferation and activation in macrophages. J Biol Chem. 278:46307–46320. Erratum in: J Biol Chem. 2005;280:13204. DOI: 10.1016/S0021-9258(19)60659-9.

26. Korovkina VP, England SK. 2002; Molecular diversity of vascular potassium channel isoforms. Clin Exp Pharmacol Physiol. 29:317–323. DOI: 10.1046/j.1440-1681.2002.03651.x. PMID: 11985543.

27. Nelson MT, Quayle JM. 1995; Physiological roles and properties of potassium channels in arterial smooth muscle. Am J Physiol. 268:C799–C822. DOI: 10.1152/ajpcell.1995.268.4.C799. PMID: 7733230.

28. Fukunaga T, Soejima H, Irie A, Sugamura K, Oe Y, Tanaka T, Kojima S, Sakamoto T, Yoshimura M, Nishimura Y, Ogawa H. 2007; Expression of interferon-gamma and interleukin-4 production in CD4+ T cells in patients with chronic heart failure. Heart Vessels. 22:178–183. DOI: 10.1007/s00380-006-0955-8. PMID: 17533522.

29. Shaw SM, Coppinger T, Waywell C, Dunne L, Archer LD, Critchley WR, Yonan N, Fildes JE, Williams SG. 2009; The effect of beta-blockers on the adaptive immune system in chronic heart failure. Cardiovasc Ther. 27:181–186. DOI: 10.1111/j.1755-5922.2009.00089.x. PMID: 19689617.

30. Yang JF, Cheng N, Ren S, Liu XM, Li XT. 2018; Characterization and molecular basis for the block of Kv1.3 channels induced by carvedilol in HEK293 cells. Eur J Pharmacol. 834:206–212. DOI: 10.1016/j.ejphar.2018.07.025. PMID: 30016664.

31. Daher C, Vimeux L, Stoeva R, Peranzoni E, Bismuth G, Wieduwild E, Lucas B, Donnadieu E, Bercovici N, Trautmann A, Feuillet V. 2019; Blockade of β-adrenergic receptors improves CD8₊T-cell priming and cancer vaccine efficacy. Cancer Immunol Res. 7:1849–1863. DOI: 10.1158/2326-6066.CIR-18-0833. PMID: 31527069.

32. Koumi S, Backer CL, Arentzen CE, Sato R. 1995; beta-Adrenergic modulation of the inwardly rectifying potassium channel in isolated human ventricular myocytes. Alteration in channel response to beta-adrenergic stimulation in failing human hearts. J Clin Invest. 96:2870–2881. DOI: 10.1172/JCI118358. PMID: 8675658. PMCID: PMC185998.

33. Smits JF, Struyker-Boudier HA. 1982; The mechanisms of antihypertensive action of beta-adrenergic receptor blocking drugs. Clin Exp Hypertens A. 4:71–86. DOI: 10.3109/10641968209061577. PMID: 6122522.

34. Benishin CG. 1990; Potassium channel blockade by the B subunit of beta-bungarotoxin. Mol Pharmacol. 38:164–169. DOI: 10.1016/S0026-895X(25)09435-0. PMID: 2385229.

35. Shafaroodi H, Asadi S, Sadeghipour H, Ghasemi M, Ebrahimi F, Tavakoli S, Hajrasouliha AR, Dehpour AR. 2007; Role of ATP-sensitive potassium channels in the biphasic effects of morphine on pentylenetetrazole-induced seizure threshold in mice. Epilepsy Res. 75:63–69. DOI: 10.1016/j.eplepsyres.2007.04.005. PMID: 17517498.

36. Premack BA, Gardner P. 1991; Role of ion channels in lymphocytes. J Clin Immunol. 11:225–238. DOI: 10.1007/BF00918180. PMID: 1724452.

37. Liang Q, Chi G, Cirqueira L, Zhi L, Marasco A, Pilati N, Gunthorpe MJ, Alvaro G, Large CH, Sauer DB, Treptow W, Covarrubias M. 2024; The binding and mechanism of a positive allosteric modulator of Kv3 channels. Nat Commun. 15:2533. DOI: 10.1038/s41467-024-46813-8. PMID: 38514618. PMCID: PMC10957983.

38. Kuenze G, Vanoye CG, Desai RR, Adusumilli S, Brewer KR, Woods H, McDonald EF, Sanders CR, George AL Jr, Meiler J. 2020; Allosteric mechanism for KCNE1 modulation of KCNQ1 potassium channel activation. Elife. 9:e57680. DOI: 10.7554/eLife.57680. PMID: 33095155. PMCID: PMC7584456.

39. Klemic KG, Shieh CC, Kirsch GE, Jones SW. 1998; Inactivation of Kv2.1 potassium channels. Biophys J. 74:1779–1789. DOI: 10.1016/S0006-3495(98)77888-9. PMID: 9545040.

40. Kopec W, Rothberg BS, de Groot BL. 2019; Molecular mechanism of a potassium channel gating through activation gate-selectivity filter coupling. Nat Commun. 10:5366. DOI: 10.1038/s41467-019-13227-w. PMID: 31772184. PMCID: PMC6879586.

Fig. 1

Structure of alprenolol.

Fig. 2

Effects of alprenolol on human Kv1.3 (hKv1.3) channel currents.

(A) Superimposed current traces for control and exposure to 50 µM and 1,000 µM alprenolol at hKv1.3 channels by voltage pulses from −50 mV to +50 mV for 2 sec with 10-mV increments every 20 sec from a holding potential of −60 mV. (B–E) Current–voltage relationships for peak and steady-state currents recorded with and without treatments with 1, 3, 10, 50, 100, 300 and 1,000 µM alprenolol for 6 or 12 min on hKv1.3 channel currents. Peak currents were recorded at the peak, whereas steady-state currents were determined at the end of depolarizing pulses. In the controls, peak and steady-state currents of +50 mV were normalized to 1. Symbols represent means ± SEM (n = 3–15).

Fig. 3

Concentration-dependent changes in human Kv1.3 (hKv1.3) channel currents by alprenolol.

Currents were induced by a 2-sec depolarizing pulse to +50 mV, starting from a holding potential of −60 mV, with and without alprenolol exposure. The normalized percentage of peak and steady-state current changes in controls were normalized as 1 and then calculated as the percentage of its increase and decrease value by benchmarking normalized 1 as 0%. (A) hKv1.3 current changes after treatment with 1, 3, 10, 50, 100, 300 and 1,000 µM alprenolol for 6 min. (B) hKv1.3 current changes after treatment with 1, 3, 10, 50, 100, 300 and 1,000 µM alprenolol for 12 min. (C) Dose–response curves after exposure to 0.3, 1, 3, 10, and 50 µM alprenolol for 6 min, with peak and steady-state current analyses. (D) Dose-dependent activation curves for peak and steady-state currents after 12-min treatments with 0.3, 1, 3, 10, and 50 µM alprenolol. Asterisks indicate statistically significant differences between peak and steady-state currents at each concentration. Symbols with error bars represent mean ± SEM (n = 3–12, *p < 0.05).

Fig. 4

Voltage and time dependence of alprenolol-induced human Kv1.3 (hKv1.3) channel current change.

Current traces elicited by 2-sec depolarization of −30 to +50 mV from a holding potential of −60 mV before and after treatment with 50 µM or 1,000 µM alprenolol. (A–D) At every voltage depolarization step, current changes with 50 µM and 1,000 µM alprenolol were normalized to the currents recorded without alprenolol exposure. Asterisks indicate statistically significant differences between peak and steady-state currents at each voltage pulse. Symbols represent means ± SEM (n = 3–8. *p < 0.05).

Fig. 5

Alprenolol-induced changes in human Kv1.3 (hKv1.3) channel activation and inactivation time courses.

The time constants for the activation and inactivation processes were determined by single exponential functions from current traces induced by a single +50 mV pulse for 2 sec from a holding potential of −60 mV. (A) Typical normalized current traces of the activation phase with and without treatment with 10, 50, and 1,000 µM alprenolol. Current traces were acquired by normalizing the data to peak values. (B) Normalized time-constant values of activation current processes with and without treatment with 10, 50, and 1,000 µM alprenolol (n = 4–8). (C) Typical inactivation phase current traces after normalization with and without treatment with 10, 50, and 1,000 µM alprenolol. (D) Normalized time-constant values of inactivation current processes with and without treatment with 10, 50, and 1,000 µM alprenolol (n = 5–8). Columns with error bars represent mean ± SEM (*p < 0.05).

Fig. 6

Absence of alprenolol-induced changes in human Kv1.3 (hKv1.3) channel steady-state activation.

(A) Typical steady-state activation tail currents measured at −50 mV after 100-msec depolarizing pulses from −70 to +60 mV with and without treatments with 50 and 1,000 µM alprenolol. (B) Steady-state activation curves were acquired by fitting the data obtained by normalizing each tail current to the tail current at +60 mV to a Boltzmann equation. Symbols represent means ± SEM (n = 3–6).

Fig. 7

Influence of alprenolol on human Kv1.3 (hKv1.3) channel steady-state inactivation.

(A) Typical tail currents were evoked by 200-msec depolarizing pulses to +40 mV; 30-sec preconditioning pulses were −70–0 mV with and without treatments with 50 and 1,000 µM alprenolol. (B) Steady-state inactivation curves were acquired by fitting the data obtained by normalizing each tail current to the tail current when depolarized to +40 mV to a Boltzmann equation. Symbols represent means ± SEM (n = 6–8).

Fig. 8

Use-dependent human Kv1.3 (hKv1.3) peak current blockade by alprenolol.

(A) Inhibition of peak current data from 80 and 40 recurrent 200-msec and +60-mV depolarization pulses from a holding potential of −80 mV at 5 and 15 sec with 1,000 µM alprenolol. (B) Inhibition of steady-state current data under the same experimental conditions as panel A. (C, D) Inhibition of peak and steady-state current data of 20 repetitive 200-msec and +60-mV depolarization pulses from a holding potential of −80 mV at 5 and 15 sec with 1,000 µM alprenolol, respectively. Current inhibition (%) = 100 × (control current − drug condition current)/control current. Control experiments were performed by repeated 200-msec depolarizing pulses (at +60 mV) starting from a holding potential (at −80 mV) at 5 and 15 sec in the absence of alprenolol. Symbols represent means ± SEM (n = 4–5).

TOOLS

Similar articles