Effect of glyceryl trinitrate on distensibility of peripheral muscular arteries in humans is not mediated by prostaglandins

Study objective — Vasodilator prostaglandins have been claimed to be responsible for the coronary haemodynamic and venodilator effects of glyceryl trinitrate, although conflicting results have been reported. The aim of this study was to evaluate whether vasodilator prostaglandins play a role in the effect of glyceryl trinitrate on the distensibility of peripheral muscular arteries in healthy humans. Design — A non-invasive technique, impedance plethysmography, was applied to the assessment of the effects of sublingual glyceryl trinitrate on the compliance of the forearm and digital arteries. The subjects studied received placebo (on two separate occasions), indomethacin (100 mg orally), or ibuprofen (800 mg orally) 1 h before glyceryl trinitrate (0.3 mg sublingual) on four occasions separated from each other by at least 48 h. Blood pressure and heart rate were measured by standard techniques; changes in peripheral arterial compliance were evaluated by impedance plethysmography of the forearm and finger. The study was double blind, cross over, placebo controlled, and randomised. Subjects — 12 healthy male volunteers were enrolled in the study. All subjects were fasting for at least 10 h and had abstained from smoking and from methylxanthine or alcohol containing beverages. Measurements and main results — Glyceryl trinitrate increased heart rate by 11.6(SEM 1.6) beats·min−1 (p