Undesser K P, Hasser E M, Haywood J R, Johnson A K, Bishop V S
Circ Res. 1985 Mar;56(3):410-7. doi: 10.1161/01.res.56.3.410.
This study compares the effect of arginine-vasopressin with phenylephrine on arterial pressure, heart rate, and renal sympathetic nerve activity in conscious rabbits with and without functional arterial baroreflexes and in rabbits with lesions of the area postrema. In intact rabbits, progressive infusions of arginine-vasopressin result in large decreases in renal sympathetic nerve activity and heart rate for a given increase in blood pressure as compared to progressive infusions of phenylephrine. In sinoaortic-denervated rabbits, the responses of arterial pressure on heart rate and renal sympathetic nerve activity to both arginine-vasopressin and phenylephrine are markedly attenuated, indicating the necessity for afferent baroreceptor activity in this response. This observation indicates that arginine-vasopressin is acting centrally to enhance the baroreflex. A central site of action of circulating vasopressin may be the area postrema, since it is the only circumventricular organ in the hindbrain. Lesioning the region of the area postrema resulted in a normalization of the responses evoked with arginine-vasopressin and phenylephrine. There was no difference in the phenylephrine responses of arterial pressure on renal sympathetic nerve activity or heart rate in area postrema-lesioned animals, compared to control rabbits. Therefore, we conclude that the area postrema or its surrounding tissue is either a site of action of circulating arginine-vasopressin or contains fibers of passage from another site where arginine-vasopressin acts to enhance baroreflex activity.
本研究比较了精氨酸加压素与去氧肾上腺素对清醒家兔动脉压、心率及肾交感神经活动的影响，这些家兔分别具有或不具有功能性动脉压力感受器反射，以及延髓后区受损的家兔。在完整的家兔中，与逐渐输注去氧肾上腺素相比，逐渐输注精氨酸加压素在血压给定升高时会导致肾交感神经活动和心率大幅下降。在窦主动脉去神经支配的家兔中，精氨酸加压素和去氧肾上腺素对动脉压、心率及肾交感神经活动的反应均明显减弱，表明该反应中传入压力感受器活动的必要性。这一观察结果表明精氨酸加压素在中枢发挥作用以增强压力感受器反射。循环血管加压素的一个中枢作用位点可能是延髓后区，因为它是后脑唯一的室周器官。损毁延髓后区区域导致精氨酸加压素和去氧肾上腺素诱发的反应恢复正常。与对照家兔相比，延髓后区受损动物中去氧肾上腺素对动脉压、肾交感神经活动或心率的反应没有差异。因此，我们得出结论，延髓后区或其周围组织要么是循环精氨酸加压素的作用位点，要么包含来自精氨酸加压素发挥作用以增强压力感受器反射活动的另一部位的纤维通道。
