Absence of age-related changes in venous responsiveness to nitroglycerin in vivo in humans.

We have previously demonstrated a progressive loss in the ability of the beta-receptor agonist isoproterenol to relax veins with increasing age. In this study the influence of age on the responsiveness of medium-sized veins to local infusions of nitroglycerin was studied in two groups of 15 healthy male volunteers using the dorsal hand vein compliance technique. A dorsal hand vein was preconstricted with submaximally effective doses of phenylephrine and a dose-response curve with nitroglycerin was established. The nitroglycerin dose that caused a 50% venodilation ranged from 0.7 to 22.4 ng/min (geometric mean 3.6 ng/min) in the younger group (aged 19 to 29 years; mean +/- SD 23 +/- 3 years) and from 0.2 to 17.9 ng/min (geometric mean 3.6 ng/min) in the older subjects (aged 50 to 74 years; mean +/- SD 63 +/- 7 years) (P = 0.49 between geometric means). The mean (+/- SD) maximal venodilation, based on the pretreatment baseline, was 103% +/- 65% in the younger and 125% +/- 64% in the older subjects (P = 0.18). These results indicate that there is no age-related change in venous responsiveness to nitroglycerin.