Comparison of age-related changes in prostaglandin E1 and beta-adrenergic responsiveness of vascular smooth muscle in adult males.
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.
Hiremath
A N
AN
Stanford University School of Medicine, Palo Alto.
Pershe
R A
RA
Hoffman
B B
BB
Blaschke
T F
TF
D000328:Adult; D000375:Aging / Q000502:physiology*; D000527:Alprostadil / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006225:Hand / Q000098:blood supply; D006801:Humans; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects; D014680:Veins / Q000187:drug effects
D011943:Receptors, Adrenergic, beta; D000527:Alprostadil; D007545:Isoproterenol