Batra S, Sjögren C, Andersson K E, Fovaeus M
Acta Physiol Scand. 1987 Aug;130(4):545-51. doi: 10.1111/j.1748-1716.1987.tb08175.x.
Omission of calcium or the inclusion of lanthanum in the bathing medium resulted in an almost complete inhibition of contractile responses induced by either K+ depolarization or carbachol in strips of rabbit urinary bladder. D-600 inhibited K+-induced contractions significantly more than carbachol-induced responses. The influx of 45Ca into cells was stimulated both by K+ depolarization and carbachol. Over a 2-min period the increase in 45Ca influx induced by high K+ and carbachol was 98 and 65%, respectively. Both lanthanum and D-600 blocked 45Ca influx stimulated by either K+ depolarization or carbachol. The inhibition of 45Ca influx by these calcium-channel blocking agents, particularly by D-600, was dependent on the length of exposure. Application of carbachol during 45Ca efflux in pre-loaded muscle strips had no effect on the rate of 45Ca efflux. These results indicate that the contractile responses of the urinary bladder to depolarization and to carbachol are highly dependent on an extracellular source of calcium.
在浴液中去除钙或加入镧会导致兔膀胱条对K⁺去极化或卡巴胆碱诱导的收缩反应几乎完全受到抑制。D - 600对K⁺诱导的收缩的抑制作用明显大于对卡巴胆碱诱导反应的抑制作用。K⁺去极化和卡巴胆碱均刺激⁴⁵Ca流入细胞。在2分钟内，高K⁺和卡巴胆碱诱导的⁴⁵Ca流入增加分别为98%和65%。镧和D - 600均阻断由K⁺去极化或卡巴胆碱刺激的⁴⁵Ca流入。这些钙通道阻滞剂，特别是D - 600，对⁴⁵Ca流入的抑制作用取决于暴露时间。在预加载肌肉条的⁴⁵Ca外流期间应用卡巴胆碱对⁴⁵Ca外流速率没有影响。这些结果表明，膀胱对去极化和卡巴胆碱的收缩反应高度依赖于细胞外钙源。
