Comparative effects of prostaglandins E1, E2, A1, F1 alpha and F2 alpha on the resistance of coronary vessels during intracoronary administration.

The effects of prostaglandins E1, E2, A1, F1 alpha, and F2 alpha on the coronary vascular resistance during intracoronary administration were studied in anaesthetized, open-chest dogs. PGE1 in doses of 0.1 - 3-10 mug/kg in single intracoronary administration produced a potent and comparatively long-lasting direct decrease of the resistance of the coronary vessels and a decrease in the systemic arterial pressure. The PGE2 and PGA1 actions on the coronary vessels were less potent. At variance with PGE1 and PGE2, the hypotensive effect of PGA1 is more expressed than its action on the resistivity of coronary vessels. PGE1 alpah and PGF2 alpha do not show any significant influence on the resistivity of the coronary vessels. The results of the investigations also permit to establish a correlation between the chemical structure and action of prostaglandins on the coronary vessels and to conclude that one of the most important functional groups that determines the prostaglandin action on the coronary vessels most decisively is the keto-group at C-9 of cyclopentane ring. As coronary dilatator agents in anaesthetized dogs, the activity of the prostaglandins ranged in the order E1 greater than E2 greater than A1 greater than F1 alpha greater than F2 alpha.