钾可诱导猪十二指肠环行肌舒张和超极化，但可诱导纵行肌收缩。
Potassium induces relaxation and hyperpolarization of circular muscles but contraction of longitudinal muscles of pig duodenum.
作者信息
Kimura I, Kimura M, Kimura M
出版信息
Br J Pharmacol. 1984 Sep;83(1):187-93. doi: 10.1111/j.1476-5381.1984.tb10134.x.
The mechanisms by which K+ relaxes circular muscles of pig duodenum were investigated, and compared with the response of the longitudinal muscles to K+. Circular muscles were concentration-dependently relaxed by 8.3-23.6 mM K+, but contracted by 47.2-143.4 mM K+. Longitudinal muscles were contracted by 11.8-94.4 mM K+. The relaxation of circular muscles was correlated with hyperpolarization (4 mV), but evoked Ca2+ spikes were not suppressed. Neither ouabain (0.14 microM) nor phentolamine (10 microM) blocked the relaxation, but tetrodotoxin (TTX, 0.63 microM) blocked both the relaxation and hyperpolarization. Mesaconitine (0.16 microM) increased the relaxation. Inhibitory junction potentials and concomitant relaxations were also blocked by TTX. The results suggest that K+-induced relaxation is caused by the release of a non-adrenergic inhibitory transmitter.
研究了钾离子使猪十二指肠环行肌松弛的机制，并与纵向肌对钾离子的反应进行了比较。8.3 - 23.6 mM的钾离子可使环行肌呈浓度依赖性松弛，但47.2 - 143.4 mM的钾离子则使其收缩。11.8 - 94.4 mM的钾离子可使纵向肌收缩。环行肌的松弛与超极化（4 mV）相关，但诱发的钙离子尖峰未被抑制。哇巴因（0.14 microM）和酚妥拉明（10 microM）均未阻断松弛作用，但河豚毒素（TTX，0.63 microM）可同时阻断松弛和超极化。中乌头碱（0.16 microM）增强了松弛作用。抑制性接头电位及伴随的松弛也被TTX阻断。结果表明，钾离子诱导的松弛是由一种非肾上腺素能抑制性递质的释放所引起的。
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