摘要

Vasoactive intestinal polypeptide (VIP) is a neuropeptide with potent circulatory effects in the adult animal and human. Little is known about its effects or mechanism of action in the immature animal. These series of experiments evaluated the effects and possible mechanism of action of VIP on the developing canine cardiovascular system. In all three series, measurements of mean heart rate and blood pressure were taken in the control state, after parasympathetic denervation with bilateral cervical vagotomies, and after autonomic blockade with propranolol (1 mg/kg) and phentolamine (0.5 mg i.v.). In series 1, we characterized the role of alpha-adrenergic receptors in early newborn puppies by investigating the hemodynamic effects of phentolamine alone in five early newborn puppies. In series 2, the hemodynamic effects of intravenous VIP infusion (0.2 microgram/kg/min) were recorded and compared in six early newborn puppies and in 10 late newborn puppies. In series 3, the hemodynamic effects of phentolamine in the presence of VIP receptor binding inhibitor were studied. In early newborn puppies, VIP had essentially no effect on heart rate or blood pressure until phentolamine was given; then, blood pressure decreased by 17% (p less than 0.005). In late newborn puppies, VIP resulted in an increase in heart rate in the control state but not after parasympathetic or sympathetic denervation. In early newborn puppies, phentolamine alone resulted in a 24% decrease (p less than 0.005) in blood pressure, compared with a 54% decrease (p less than 0.005) in early newborn puppies preexposed to VIP infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

译文

血管活性肠多肽 (VIP) 是一种在成年动物和人类体内具有强大循环作用的神经肽。对其在未成熟动物中的作用或作用机制知之甚少。这些系列实验评估了 VIP 对发展中的犬心血管系统的影响和可能的作用机制。在所有三个系列中，平均心率和血压的测量是在对照状态下进行的，在双侧宫颈迷走神经切断后，在心得安 (1 毫克/千克) 自主神经阻滞后进行的和酚妥拉明 (0.5 毫克 i。 v.)。在系列 1 中，我们通过研究酚妥拉明单独在 5 只早期新生幼犬中的血流动力学效应，描述了 α-肾上腺素能受体在早期新生幼犬中的作用。在系列 2 中，记录并比较了静脉注射 VIP (0.2 微克/千克/分钟) 对 6 只早期新生幼犬和 10 只晚期新生幼犬的血流动力学影响。在系列 3 中，研究了在 VIP 受体结合抑制剂存在下酚妥拉明的血流动力学效应。在早期新生幼犬中，在给予酚妥拉明之前，VIP 对心率或血压基本没有影响; 然后，血压下降了 17% (p 小于 0.005)。在晚期新生幼犬中，VIP 导致在控制状态下的心率增加，但在副交感神经或交感神经去神经支配后没有。在早期新生幼犬中，酚妥拉明单独导致血压下降 24% (p 低于 0.005)，而血压下降 54% (p 低于 0.005) 在暴露于 VIP 输注的早期新生小狗中。 (摘要删减为 250 字)