Courtice G P, Kwong T E, Lumbers E R, Potter E K
J Physiol. 1984 Sep;354:547-56. doi: 10.1113/jphysiol.1984.sp015392.
In unanaesthetized sheep, the sensitivity of the baroreceptor-cardio-inhibitory reflex was greater when intravenous vasopressin was used to raise blood pressure, than when intravenous phenylephrine was used to raise blood pressure. This difference was still evident in animals in which beta-adrenergic blockade had been carried out using propranolol. In the presence of combined beta-adrenergic and muscarinic blockade, a direct negative chronotropic effect of intravenous vasopressin could not be demonstrated. It was concluded, therefore, that intravenous vasopressin enhanced cardiac vagal tone. This effect of vasopressin on efferent cardiac vagal tone was confirmed directly in anaesthetized dogs by recording from single cardiac vagal efferent fibres. Furthermore, recordings from single carotid sinus baroreceptor fibres did not demonstrate a direct action of vasopressin on the sensitivity of the baroreceptors. However, the pressor effect of vasopressin is associated with a greater increase in efferent cardiac vagal discharge than that seen when equipressor doses of phenylephrine are given, or when blood pressure is raised by a similar amount by inflation of an intra-aortic balloon. Studies in isolated guinea-pig atrial preparations and in anaesthetized rabbits and dogs, revealed no consistent peripheral action of vasopressin on the action of the vagus at the heart.
在未麻醉的绵羊中，静脉注射血管加压素升高血压时，压力感受器 - 心抑制反射的敏感性高于静脉注射去氧肾上腺素升高血压时。在使用普萘洛尔进行β - 肾上腺素能阻滞的动物中，这种差异仍然明显。在同时存在β - 肾上腺素能和毒蕈碱阻滞的情况下，无法证明静脉注射血管加压素具有直接的负性变时作用。因此得出结论，静脉注射血管加压素增强了心脏迷走神经张力。通过记录单个心脏迷走神经传出纤维，在麻醉犬中直接证实了血管加压素对心脏迷走神经传出张力的这种作用。此外，单个颈动脉窦压力感受器纤维的记录未显示血管加压素对压力感受器敏感性有直接作用。然而，与给予等压剂量的去氧肾上腺素时相比，或与通过主动脉内气囊充气使血压升高相似幅度时相比，血管加压素的升压作用伴随着心脏迷走神经传出放电的更大增加。对离体豚鼠心房标本以及麻醉兔和犬的研究表明，血管加压素对迷走神经在心脏的作用没有一致的外周作用。
