Effects of nerve stimulation and of administration of noradrenaline or potassium chloride upon the release of prostaglandins, I2, E2, and F2 alpha from te perfused mesenteric arterial bed of the rabbit.

1 The release of prostaglandin I2 (PGI2), PGE2 and PGF2 alpha from the perfused mesenteric arterial bed of the rabbit was examined at rest, following nerve stimulation and following noradrenaline (NA) or potassium chloride (KCl) administration. 2 Stimulation of adrenergic nerves at 10 Hz caused a significant increase in the release of both PGI2, (assayed in terms of 6-oxo-PGF1 alpha) and PGE2 but a significant decrease in the release of PGF2 alpha. 3 Exogenous Na (2 micrograms) increased the output of PGI2 and PGE2 but left the output of PGF2 alpha unaffected. 4 KCl (15 mg) significantly increased the output of PGF2 alpha but left the output of PGF2 unaffected. 5 It is concluded that PGI2 and PGE2 output from the mesenteric arterial bed of the rabbit increases following stimulation of adrenoceptors. The sympathetic nervous system may therefore modulate PGI2/platelet interaction. 6 Prostaglandins released from the blood vessels by sympathetic nerve stimulation may also modulate adrenergic transmission to the blood vessels.