Abstract
Interstitial cells of Cajal (ICC) evoke pacemaker activities in many tissues. The purpose of this study was to investigate the relationship between interstitial cell and pacemaker activity in the human ureter through the recording of spontaneous contractions. Spontaneous contractions of eight circular and longitudinal smooth muscle strips of the human ureter to acetylcholine (ACh) and/or norepinephrine (NE) were observed. Human ureteral strips were divided into proximal and distal groups, and each group was subdivided into circular and longitudinal groups. The proximal group showed spontaneous activities of 3∼4 times within 5 minutes in the longitudinal group. ACh (10–4 M) augmented the frequency of the spontaneous contractions. The cumulative application of NE also augmented the frequency in a dose-dependent manner. The effects of NE application were inhibited by concomitant application of 10–5 M glibenclamide. Receptor tyrosine kinase (c-kit) staining revealed abundant ICCs only in proximal tissues. Therefore, spontaneous contractions of the human ureter might be modulated by ICC in the proximal region, and the actions might be related with the activation of cholinergic and/or adrenergic system mediated by a glibenclamide-sensitive pathway.
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Fig. 1.
(A) Typical tracing of spontaneous contractions of longitudinal strip (PG-LG) of human ureter to ACh (10–9∼10–4 M). (B) 10–4 M ACh application slightly, but significantly increased frequency of the responses (n=12, ∗Means p<0.05).
![kjpp-15-37f1.tif](/upload/SynapseXML/0067kjpp/thumb/kjpp-15-37f1.gif)
Fig. 2.
Accumulative application of NE significantly increased the frequency of responses dose-dependently recorded in longitudinal strip (PG-LG) of human ureter (n=12, ∗Means p<0.05).
![kjpp-15-37f2.tif](/upload/SynapseXML/0067kjpp/thumb/kjpp-15-37f2.gif)
Fig. 3.
NE (10–4 M) application also significantly increased frequency of the responses recorded in circular strips (PG-CG) of human ureter (n=9, ∗Means p<0.05).
![kjpp-15-37f3.tif](/upload/SynapseXML/0067kjpp/thumb/kjpp-15-37f3.gif)