维拉帕米对盐酸降低胃粘膜细胞外Ca^(2+)活度和跨粘膜电位效应的影响

Effects of Verapamil on HCI-Induced Decrease of Extracellular Ca^(2+)Activit and Transmucosal Potential Difference in Toad Antrum Mucosa

应用钙离子选择微电极技术,观察了维拉帕米和异丙肾上腺素对由酸化蟾蜍胃窦粘膜引起的细胞外Ca^(2+)活度和跨粘膜电位下降效应的影响。实验结果表明,维拉帕米抑制盐酸降低细胞外Ca^(2+)活度和跨粘膜电位的效应,而异丙肾上腺素则增强细胞外Ca^(2+)活度的下降效果,但对跨粘膜电位的下降则无明显影响。结果提示,由盐酸刺激引起的胃窦粘膜细胞外Ca^(2+)活度的下降很可能是由于Ca^(2+)向细胞内转移的量增加所致。

The effects of verapamil and isoprenaline on HCI—induced decrease of extracellular calcium ion activity and transmucosal potential difference in the toad gastric antrum mucosa were studied using calcium ion selective microelectrode and common microelectrode techniques in vitro. The actions of HCI were inhibited significantly by the pretreatment of verapamil (2.3×10^(-5)mol/L). However, the HCI—induced decreasing effect of extracellular calcium ion activity was facilitated by the pretreatment of isoprenaline (1.1×10^(-5)mol/L), while the decreasing effect of transmucosal potential difference was not affected. The results suggest that the decrease of extraceUular calcium ion activity induced by the acidification of the antrum mucosa is related to the increase of calcium ion getting into the cells.