Wall B M, Huch K M, Runyan K R, Williams H H, Gavras H, Cooke C R
Veterans Affairs Medical Center, Memphis, Tennessee, USA.
Am J Physiol. 1996 Feb;270(2 Pt 2):R356-64. doi: 10.1152/ajpregu.1996.270.2.R356.
The response of vasopressin and its role in the maintenance of arterial pressure during and after development of hypotensive central hypovolemia were studied in tilt table studies in quadriplegic subjects. The studies were performed during acute head-up tilting to a maximally tolerated degree of tilt (8 subjects) and during sustained head-up tilt following a 20% reduction in mean arterial pressure (MAP) (11 subjects). Studies in all subjects were performed on two separate days, once with and once without administration of a selective vasopressin V1-receptor antagonist. During acute head-up tilting, plasma vasopressin concentrations (PAVP) did not increase significantly until MAP decreased to approximately 60 mmHg at maximal tilt. There was no difference in the degree of hypotension produced in the presence compared with the absence of V1-receptor blockade. There was also no difference in plasma renin activity (PRA) or in plasma cortisol or aldosterone concentrations at maximal tilt. In contrast, during sustained head-up tilt following a 20% reduction in arterial pressures, systolic and mean arterial pressures were significantly lower and PRA was significantly higher in the presence than in the absence of V1-receptor blockade. PAVP increased and was significantly higher after 30 min of sustained tilt than pretilt PAVP in supine posture. These studies do not provide evidence of a role for vasopressin in the maintenance of arterial pressure during the acute development of hypotensive hypovolemia in human subjects, but they do provide evidence of a modest role for vasopressin in the maintenance of arterial pressure when the effect of hypovolemia is more moderate and sustained.
在四肢瘫痪患者的倾斜台研究中，研究了加压素的反应及其在低血压性中枢性低血容量发生期间和之后维持动脉压的作用。这些研究在急性头高位倾斜至最大耐受倾斜度时进行（8名受试者），以及在平均动脉压（MAP）降低20%后的持续头高位倾斜期间进行（11名受试者）。所有受试者的研究均在两个不同的日子进行，一次给予选择性加压素V1受体拮抗剂，一次不给予。在急性头高位倾斜期间，直到最大倾斜时MAP降至约60 mmHg，血浆加压素浓度（PAVP）才显著增加。存在V1受体阻断与不存在时产生的低血压程度没有差异。最大倾斜时血浆肾素活性（PRA）、血浆皮质醇或醛固酮浓度也没有差异。相比之下，在动脉压降低20%后的持续头高位倾斜期间，存在V1受体阻断时的收缩压和平均动脉压显著更低，PRA显著更高。PAVP增加，且在持续倾斜30分钟后显著高于仰卧位倾斜前的PAVP。这些研究没有提供加压素在人类受试者低血压性低血容量急性发展期间维持动脉压中起作用的证据，但确实提供了证据表明当低血容量的影响更中度且持续时，加压素在维持动脉压中起适度作用。
