Effect of inhibition of prostaglandin synthesis on sympathetic nervous system function in man

The effect of inhibition of prostaglandin synthesis by indomethacin on the function of the peripheral sympathetic nervous system was studied in eight normotensive subjects. Sympathetic nervous function was assessed by measurement of plasma norepinephrine, alpha-adrenergic receptor sites on platelet membranes, and urinary excretion of epinephrine and norepinephrine. Treatment with indomethacin for 7 days resulted in significant decreases in basal plasma norepinephrine from 134 +/- 7 to 99 +/- 6 (SEM) pg/ml (P less than 0.01), a 26% decrease. Posturally stimulated norepinephrine concentrations (337 +/- 14 pg/ml in control studies) were 255 +/- 18 pg/ml (P less than 0.02), 25% lower, with indomethacin. Plasma norepinephrine after 5-min compression of hand grip (468 +/- 47 pg/ml in control) was 331 +/- 30 pg/ml (P less than 0.005), 29% lower, with indomethacin. The number of platelet alpha-adrenergic receptor sites did not change with indomethacin, nor did prostaglandin E1-stimulated cAMP production by platelet membranes. In addition, indomethacin produced no change in urinary excretion of norepinephrine or epinephrine. It is suggested that inhibition of prostaglandin synthesis may lead, via baroreceptor feedback, to a decrease in plasma norepinephrine concentration.