Isolated dog coronary arteries response to glomerulopressin

Coronary arteries were excised from pentobarbital anesthetized normal dogs. The isolated coronary arteries were placed in an oxigenated KRB bathing solution maintained at 37 degrees C and pH 7.4 changes in the basal tone were measured. The addition of glomerulopressin to the bathing solution produced a decrease of 26 +/- 1.5 mg of the basal tone. This decrease was prolonged for more than 40 minutes. Several inhibitors of prostaglandins synthesis were added to the bath such as corticosterone (2 X 10(-5) M), indomethacin (6 X 10(-6) M), acetylsalicylic acid (1.8 X 10(-4) M) and tranylcypromine (4 X 10(-4) M). All these inhibitors blocked the action of glomerulopressin. We conclude that glomerulopressin relaxes the coronary arteries and that this relaxation may be mediated through the novobiosynthesis of prostaglandins.