Levin R M, Zderic S A, Ewalt D H, Duckett J W, Wein A J
Division of Urology, Hospital of the University of Pennsylvania, Philadelphia.
Pharmacology. 1991;43(2):69-77. doi: 10.1159/000138830.
The contractile response of the rabbit urinary bladder to field stimulation consists of both cholinergic and purinergic components. In general, approximately 60% of the contractile response to field stimulation is cholinergic and 40% is purinergic. Although the purinergic response represents a significant proportion of the initial (phasic) pressure response to field stimulation of the isolated whole bladder, it contributes only 10-15% of the ability of field stimulation to empty the bladder. The current study investigates the effects of pregnancy on the contractile responses of the isolated urinary bladder to cholinergic and purinergic stimulation. The results of these studies indicate that pregnancy induces substantial changes in the physiology and pharmacology of the urinary bladder. The following data are consistent with the theory that pregnancy substantially increases the relative purinergic component of the response to field stimulation (and presumably neuronal stimulation): (1) there was a significantly greater response of the bladders isolated from pregnant rabbits to low-frequency field stimulation; (2) atropine was more effective at inhibiting the pressure generation of bladders isolated from virgin female rabbits; (3) field stimulation was more effective at emptying bladders isolated from virgin female rabbits; (4) the response of the bladders from pregnant rabbits to bethanechol was significantly reduced, whereas the response to ATP was significantly increased. In addition to these effects of pregnancy on bladder physiology, pregnancy induced a 50% decrease in the muscarinic receptor density of the urinary bladder body, which correlated very well with the 50% decrease in the contractile response to bethanechol.
兔膀胱对场刺激的收缩反应包括胆碱能和嘌呤能成分。一般来说，对场刺激的收缩反应中约60%是胆碱能的，40%是嘌呤能的。尽管嘌呤能反应在离体全膀胱对场刺激的初始（相性）压力反应中占相当大的比例，但它对场刺激排空膀胱能力的贡献仅为10 - 15%。本研究调查了妊娠对离体膀胱对胆碱能和嘌呤能刺激的收缩反应的影响。这些研究结果表明，妊娠会引起膀胱生理和药理学的显著变化。以下数据与妊娠会大幅增加对场刺激（可能还有神经元刺激）反应中相对嘌呤能成分的理论一致：（1）从妊娠兔分离的膀胱对低频场刺激的反应明显更大；（2）阿托品对抑制未孕雌性兔分离膀胱的压力产生更有效；（3）场刺激对排空未孕雌性兔分离膀胱更有效；（4）妊娠兔膀胱对氨甲酰甲胆碱的反应显著降低，而对ATP的反应显著增加。除了妊娠对膀胱生理的这些影响外，妊娠还导致膀胱体毒蕈碱受体密度降低50%，这与对氨甲酰甲胆碱收缩反应降低50%密切相关。
