On the mechanism of reserpine action on uterine musculature

ABSTRACT

Physiological and biochemical studies were conducted to ascertain the nature and mechanism of Reserpine relaxing action on uterine muscle. Various animal and human myometrial specimens were utilized involving in vitro, in vivo and manometric setupsWhile Reserpine and the catechol amines, Epinephrine and Norepinephrine, similarly inhibit uterine contractions, the effects of the Rauwolfia alkaloid cannot be due to release and mediation of the latter autonomic agents. Experimental proofs offered include (a) Reserpine effects are not prevented nor significantly diminished by adrenergic blocking agents such as Phentolamine and Guanethidine; (b) In pregnant cats, the catechol amines exhibit a stimulant action on the uterus. Reserpine administration elicits the usual inhibitory effect under such conditionReserpine inhibitory effects on the myometrial tissues are elicited directly on the effector contractile mechanisms. Specific pharmacological antagonism of smooth muscle agonists such as Ergonovine, Posterior Pituitary Injection, Oxytocin, Barium, etc. are consistently observed indicating a musculotrophic actionReserpine inhibits significantly and uniformly the oxygen consumption of uterine tissues as borne out by direct Warburg manometry. There appears to be a qualitative correlation between myometrial inhibition and this biochemical phenomenon. (Summary and Conclusions)