Blank M A, Kimura K, Fuortes M, Jaffe B M
Department of Surgery, State University of New York Health Science Center, Brooklyn 11203.
Am J Physiol. 1990 Aug;259(2 Pt 1):G252-7. doi: 10.1152/ajpgi.1990.259.2.G252.
The effect of the vasoactive intestinal polypeptide (VIP) antagonist [N-Ac-Tyr1,D-Phe2]-GRF-(1-29)-NH2 on pelvic nerve-induced colonic vasodilation and VIP release was investigated in chloralose-anesthetized cats. VIP antagonist (10 and 50 nmol/kg in saline) or saline alone was injected into a branch of the superior mesenteric artery immediately before bilateral pelvic nerve stimulation. The increase in conductance in the inferior mesenteric artery during pelvic nerve stimulation was reduced in an apparently dose-dependent fashion by the VIP antagonist (by 35 +/- 10 and 42 +/- 9%, respectively) compared with the pelvic nerve-induced increase in conductance after injection of saline alone. Injection of the VIP antagonist (50 nmol/kg) did not alter conductance in the absence of pelvic nerve stimulation. VIP was released into portal venous blood during pelvic nerve stimulation in the presence of the antagonist (from 103 +/- 29 to 165 +/- 45 pmol/l). This was not significantly different from release in the presence of saline. The effect of the VIP antagonist (10 nmol.kg-1.min-1) on inferior mesenteric arterial vasodilation induced by exogenous VIP was also quantitated. The increase in conductance after VIP injection (0.2 nmol/kg) was significantly reduced when accompanied by simultaneous infusion of the VIP antagonist (by 54 +/- 6%) compared with the increase in conductance during simultaneous infusion of saline. We conclude that [N-Ac-Tyr1,D-Phe2]-GRF-(1-29)-NH2 is an inhibitor of pelvic nerve-induced vasodilation in the feline colon and does not act by modulating VIP release.(ABSTRACT TRUNCATED AT 250 WORDS)
在水合氯醛麻醉的猫身上，研究了血管活性肠肽（VIP）拮抗剂[N-乙酰-Tyr1，D-苯丙氨酸2]-GRF-(1-29)-NH2对盆神经诱导的结肠血管舒张和VIP释放的影响。在双侧盆神经刺激前，将VIP拮抗剂（10和50 nmol/kg溶于生理盐水）或仅生理盐水注入肠系膜上动脉的一个分支。与仅注射生理盐水后盆神经诱导的电导增加相比，VIP拮抗剂使盆神经刺激期间肠系膜下动脉的电导增加以明显的剂量依赖性方式降低（分别降低35±10%和42±9%）。在没有盆神经刺激的情况下，注射VIP拮抗剂（50 nmol/kg）不会改变电导。在存在拮抗剂的情况下，盆神经刺激期间VIP释放到门静脉血中（从103±29到165±45 pmol/l）。这与存在生理盐水时的释放没有显著差异。还定量研究了VIP拮抗剂（10 nmol.kg-1.min-1）对外源性VIP诱导的肠系膜下动脉血管舒张的影响。与同时输注生理盐水期间的电导增加相比，当同时输注VIP拮抗剂时，注射VIP（0.2 nmol/kg）后的电导增加显著降低（降低54±6%）。我们得出结论，[N-乙酰-Tyr1，D-苯丙氨酸2]-GRF-(1-29)-NH2是猫结肠中盆神经诱导的血管舒张的抑制剂，并且不是通过调节VIP释放起作用的。（摘要截短至250字）
