Arruda J A, Sabatini S
Am J Physiol. 1980 Aug;239(2):F154-9. doi: 10.1152/ajprenal.1980.239.2.F154.
The effect of carbachol on water transport by the toad bladder was studied. Carbachol caused a small increase in base-line water flow and inhibited, partially, vasopressin- (AVP) or cyclic AMP-stimulated water flow. The effect of carbachol on base-line or AVP-stimulated water flow was totally prevented by atropine, indicating that the effect of cabachol on water transport is mediated through a muscarinic receptor. Carbachol caused a significant increase in 45Ca uptake by toad bladder; this increase in calcium uptake could be prevented by atropine, pentobarbital, or lanthanum. The effect of carbachol on base-line and AVP-stimulated water flow was also prevented by pentobarbital or lanthanum, suggesting that the effect of carbachol is mediated, at least in part, by an increase in calcium uptake. The ionophore A-23187, an agent that increased 45Ca uptake, also enhanced base-line water flow and inhibited AVP-stimulated water flow. The effects of carbachol and the ionophore A-23187 on base-line water flow, AVP-stimulated water flow, and on calcium uptake were not additive, suggesting that both agents alter water transport by a similar mechanism. These data demonstrate that carbachol stimulates base-line water transport and inhibits AVP-stimulated water transport. They suggest that the alteration in water transport induced by carbachol is related to an increase in calcium uptake.
研究了卡巴胆碱对蟾蜍膀胱水转运的影响。卡巴胆碱使基线水流量略有增加，并部分抑制血管加压素（AVP）或环磷酸腺苷刺激的水流量。阿托品可完全阻止卡巴胆碱对基线或AVP刺激的水流量的影响，表明卡巴胆碱对水转运的作用是通过毒蕈碱受体介导的。卡巴胆碱使蟾蜍膀胱对45Ca的摄取显著增加；这种钙摄取的增加可被阿托品、戊巴比妥或镧阻止。戊巴比妥或镧也可阻止卡巴胆碱对基线和AVP刺激的水流量的影响，提示卡巴胆碱的作用至少部分是由钙摄取增加介导的。离子载体A - 23187可增加45Ca的摄取，也可增强基线水流量并抑制AVP刺激的水流量。卡巴胆碱和离子载体A - 23187对基线水流量、AVP刺激的水流量以及钙摄取的作用并非相加的，提示这两种药物通过相似的机制改变水转运。这些数据表明卡巴胆碱刺激基线水转运并抑制AVP刺激的水转运。它们提示卡巴胆碱诱导的水转运改变与钙摄取增加有关。
