Brand P H, Metting P J, Britton S L
Department of Physiology, Medical College of Ohio, Toledo 43699.
Am J Physiol. 1988 Sep;255(3 Pt 2):H483-91. doi: 10.1152/ajpheart.1988.255.3.H483.
The roles of the autonomic nervous system, vasopressin, and angiotensin II in support of blood pressure were evaluated in seven conscious, resting dogs while hydrated or dehydrated. Mean arterial blood pressure (MAP) was monitored, and the dogs were given hexamethonium to block autonomic ganglia. Thirty minutes later, they were given captopril, and after another 30 min, a vasopressin V1 antagonist, d(CH2)5TyrMeAVP, was given. The order okf administration of captopril and d(CH2)5TyrMeAVP was alternated in different experiments. Hexamethonium had no effect on steady-state MAP in either hydrated or dehydrated dogs. In hydrated dogs, the average MAP was 100 mmHg; d(CH2)5TyrMeAVP decreased MAP by approximately 12 mmHg, and captopril decreased MAP by 24 mmHg. The magnitude of the effect of these two inhibitors was independent of the order of their administration. Dehydration doubled the effect of d(CH2)5TyrMeAVP on MAP but had no effect on the response to captopril. The results suggest that 1) autonomic function is not essential for maintenance of arterial blood pressure in resting dogs; 2) during autonomic ganglionic blockade, arterial blood pressure is supported by both angiotensin II and vasopressin; and 3) dehydration increases the role of vasopressin in control of blood pressure.
在七只清醒、静息状态的犬身上，分别在其处于水合状态或脱水状态时，评估了自主神经系统、血管升压素和血管紧张素II在维持血压方面的作用。监测平均动脉血压（MAP），并给犬注射六甲铵以阻断自主神经节。30分钟后，给它们注射卡托普利，再过30分钟，给予血管升压素V1拮抗剂d(CH2)5TyrMeAVP。在不同实验中，交替改变卡托普利和d(CH2)5TyrMeAVP的给药顺序。六甲铵对处于水合状态或脱水状态的犬的稳态MAP均无影响。在水合状态的犬中，平均MAP为100 mmHg；d(CH2)5TyrMeAVP使MAP降低约12 mmHg，卡托普利使MAP降低24 mmHg。这两种抑制剂作用的大小与给药顺序无关。脱水使d(CH2)5TyrMeAVP对MAP的作用加倍，但对卡托普利的反应无影响。结果表明：1）自主神经功能对于静息状态犬维持动脉血压并非必不可少；2）在自主神经节阻断期间，动脉血压由血管紧张素II和血管升压素共同维持；3）脱水增加了血管升压素在控制血压中的作用。
