Korolkiewicz R, Takeuchi K, Sliwinski W, Konstanski Z, Rekowski P, Szyk A
Department of Pharmacology, Medical University of Gdansk, Do Studzienki 38, Gdansk, 80-227, Poland.
Pharmacol Res. 1997 Aug;36(2):147-51. doi: 10.1006/phrs.1997.0217.
Galanin (3-300 nM) evoked reproducible concentration-dependent contractions of rat isolated gastric fundus strips, EC50 of the peptide equalled 16.7 nM (6.2-39.2) and the slope of the concentration-response curve was 34.8 (24.0-45.7). The maximal response (Emax) to carbachol (30 nM) was not affected by the absence of the potassium ions in the bathing solution. On the contrary the Emax to galanin (300 nM) was decreased by almost 95% by the use of the potassium-free buffer. Re-exposure of the muscle strips to potassium containing bathing medium reversed the inhibition by about 35%, yet the value remained significantly lower than that of the control. Apamin (1 and 2 microM), glybenclamide (10 microM), clofilium tosylate (10 microM) did not significantly influence the Emax to carbachol. Apamin or glybenclamide did not affect the contractile action of galanin, while clofilium attenuated the Emax to the peptide in a concentration-dependent manner, the EC50 of the agent being 9.44 microM (164 nM-541 microM). It was concluded that the potassium ions play a modulatory role in gastric smooth muscle contraction following galanin receptor stimulation, probably by interacting with the extracellular calcium influx.
甘丙肽（3 - 300 nM）可引起大鼠离体胃底条带产生可重复的浓度依赖性收缩，该肽的半数有效浓度（EC50）为16.7 nM（6.2 - 39.2），浓度 - 反应曲线的斜率为34.8（24.0 - 45.7）。对卡巴胆碱（30 nM）的最大反应（Emax）不受浴液中无钾离子的影响。相反，使用无钾缓冲液可使对甘丙肽（300 nM）的Emax降低近95%。将肌条重新暴露于含钾的浴液中可使抑制作用逆转约35%，但该值仍显著低于对照组。蜂毒明肽（1和2 μM）、格列本脲（10 μM）、甲苯磺酸氯菲铵（10 μM）对卡巴胆碱的Emax无显著影响。蜂毒明肽或格列本脲不影响甘丙肽的收缩作用，而甲苯磺酸氯菲铵以浓度依赖性方式减弱对该肽的Emax，该药物的EC50为9.44 μM（164 nM - 541 μM）。得出的结论是，钾离子在甘丙肽受体刺激后对胃平滑肌收缩起调节作用，可能是通过与细胞外钙内流相互作用实现的。
