Cumulative and noncumulative dose-response curves to noradrenaline on the dorsal hand vein

Abstract

Cumulative and noncumulative dose-response curves to noradrenaline were compared in the human dorsal hand vein (DHV), using the DHV compliance technique. This technique involves recording changes in the diameter of a superficial hand vein at a constant congestion pressure. Twelve healthy male volunteers (20–45 years) participated in one experimental session. Five incremental doses of noradrenaline acid tartrate (0.33–33.33 ng min −1) were infused twice in each subject: first with 5-min washout (5% dextrose saline) periods in between (“noncumulative dose-response curve”), then without interspersed washout periods (“cumulative dose-response curve”). Two-factor analysis of variance (dose of noradrenaline × method of infusion) showed a significant effect of dose ( F = 101.53, df = 4,44, p < 0.0001); however, there was no significant effect of method of infusion ( F = 0.21, df = 1,11, p > 0.1), indicating that cumulative and noncumulative applications of noradrenaline resulted in similar dose-response curves. Neither method of noradrenaline application had any effect on systemic blood pressure and heart rate. Construction of cumulative dose-response curves allows the study of the interactions of noradrenaline with a systemically taken antagonist during a narrow time window and the construction of more than one dose-response curve within the same experimental session.