Pomeranz I S, Davison J S, Shaffer E A
Dig Dis Sci. 1983 Jun;28(6):539-44. doi: 10.1007/BF01308156.
In vivo studies have indicated that pancreatic polypeptide induces gallbladder relaxation, whereas motilin initiates contraction of the gallbladder. To determine if these two polypeptides act directly on the gallbladder muscle, their effect on strips of human gallbladder was studied in vitro. Preparations were suspended in an organ bath and the isometric tension recorded. Dose-response curves to cholecystokinin and acetylcholine were first established. The ability of pancreatic polypeptide to cause relaxation under basal conditions and during 50% maximal stimulation by cholecystokinin-octapeptide (2 X 10(-8) M) was assessed on four strips at approximate physiological concentration (300 pmol/liter) and on four additional strips at 10(3) higher concentration. Pancreatic polypeptide did not have any effect on the basal or the cholecystokinin-generated tension at either concentration. The response to motilin was evaluated on four gallbladder strips at concentrations ranging from 10(-11) to 6.7 X 10(-7) M. Although the highest concentration was more than 10(5) greater than levels reported in fasting serum, motilin did not initiate any gallbladder strip contraction. Whereas the preparation was unresponsive to pancreatic polypeptide and motilin, it was capable of contracting in a dose-related fashion to the known agonists cholecystokinin and acetylcholine, and the response was blocked by the respective antagonists dibutyryl cyclic GMP and atropine. It thus seems that pancreatic polypeptide and motilin exert their respective actions as sites remote from the gallbladder without directly affecting gallbladder muscle.
体内研究表明，胰多肽可诱导胆囊舒张，而胃动素则引发胆囊收缩。为了确定这两种多肽是否直接作用于胆囊肌肉，我们在体外研究了它们对人胆囊条的影响。将标本悬挂于器官浴槽中并记录等长张力。首先建立了对胆囊收缩素和乙酰胆碱的剂量-反应曲线。在大约生理浓度（300 pmol/升）的四条标本以及浓度高10³倍的另外四条标本上，评估了胰多肽在基础条件下以及在八肽胆囊收缩素（2×10⁻⁸ M）50%最大刺激期间引起舒张的能力。胰多肽在这两种浓度下对基础张力或胆囊收缩素产生的张力均无任何影响。在四条胆囊条上评估了胃动素在10⁻¹¹至6.7×10⁻⁷ M浓度范围内的反应。尽管最高浓度比空腹血清中报道的水平高10⁵倍以上，但胃动素并未引发任何胆囊条收缩。虽然该标本对胰多肽和胃动素无反应，但它能够以剂量相关的方式对已知激动剂胆囊收缩素和乙酰胆碱产生收缩反应，并且该反应被各自的拮抗剂二丁酰环鸟苷酸和阿托品阻断。因此，似乎胰多肽和胃动素在远离胆囊的部位发挥各自的作用，而不直接影响胆囊肌肉。
