Hiremath A N, Pershe R A, Hoffman B B, Blaschke T F
Stanford University School of Medicine, Palo Alto.
J Gerontol. 1989 Jan;44(1):M13-7. doi: 10.1093/geronj/44.1.m13.
Aging in humans is associated with a general decline in beta-adrenergic receptor responsiveness. Whether this is a consequence of a defect at the receptor level or along the adenylate cyclase pathway is not known. Using a technique to measure compliance of dorsal hand veins, we investigated the venodilatory response to isoproterenol and prostaglandin E1 (PGE1), which interact with distinct membrane-bound receptors but activate the same adenylate cyclase system. Studies were conducted in 7 young (Y, less than 30 years) and 7 elderly (E, greater than 60 years) healthy male volunteers. Dilatation induced by isoproterenol (mean +/- SD) was 43 +/- 8% in E vs 97 +/- 17% in Y, p = .003. However, PGE, produced complete relaxation in both Y and E subjects (122 +/- 17% vs 97 +/- 19% respectively, p = .270). The sensitivity to PGE1 was not significantly different between the Y and E. Our results demonstrate that PGE1 is a potent venodilator in humans and that the age-related decline in vascular response is specific to beta-adrenoceptor agonists and does not reflect a generalized loss in responsiveness to adenylate cyclase coupled receptors.
人类衰老与β-肾上腺素能受体反应性普遍下降有关。目前尚不清楚这是受体水平缺陷还是沿腺苷酸环化酶途径缺陷的结果。我们采用一种测量手背静脉顺应性的技术，研究了异丙肾上腺素和前列腺素E1（PGE1）的静脉舒张反应，这两种物质与不同的膜结合受体相互作用，但激活相同的腺苷酸环化酶系统。研究在7名年轻（Y，小于30岁）和7名老年（E，大于60岁）健康男性志愿者中进行。异丙肾上腺素诱导的扩张（均值±标准差）在E组为43±8%，在Y组为97±17%，p = 0.003。然而，PGE1在Y组和E组受试者中均产生了完全舒张（分别为122±17%和97±19%，p = 0.270）。Y组和E组对PGE1的敏感性无显著差异。我们的结果表明，PGE1是一种有效的人体静脉舒张剂，与年龄相关的血管反应下降是β-肾上腺素能受体激动剂特有的，并不反映对腺苷酸环化酶偶联受体反应性的普遍丧失。
