Role of PGE2 in the modulation of the adrenergic response in man

The influence of sympathetic stimulation (SS) (achieved by 2 min cold application) on the plasma concentration of PGE2, PGF2 alpha (radioimmunoassay), noradrenaline (NA) and adrenaline (A) (radioenzymatic assay) and on forearm vascular resistance (indirect measurement, FVR) was studied in 16 healthy volunteers before and after cyclooxygenase inhibition by indomethacin (200 mg per day orally for 3 days) and lysine acetylsalicylate (corresponding to 10 mg X kg-1 of acetylsalicylic acid -ASA- iv). SS induced a sharp increase in PGE2 (from 8.1 +/- 4.3 pg X ml-1 before SS to 23.9 +/- 6.5, P less than 0.001 2 min after the beginning of SS and then to 18.9 +/- 10.2, P less than 0.001 to 8.4 +/- 3.9, NS, 4 and 12 min respectively after the beginning of SS). Plasma levels of PGF2 alpha remained undetectable both before and after SS. The increase in PGE2 was associated with a simultaneous increase in NA (from 13.4 +/- 24.2 to 204.1 +/- 67.2 pg X ml-1, P less than 0.001 during SS and 140.6 +/- 39.5, NS at the end of the experiment), whereas A did not vary significantly. FVR increased significantly only during SS. ASA did not affect PGE2 and NA plasma levels at rest or after SS. No PGE2 was detected during IND administration either before or after SS. IND significantly increased NA plasma concentration at the observation made 12 min after the beginning of SS (185.2 +/- 64.3 pg X ml-1 vs basal values of 135.9 +/- 46.2 pg X ml-1, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)