Influence of steroid ovarian hormones and calcium on drug-induced contractions of the isolated immature uterine muscle of mouse. An analysis of histamine receptor system.

1. Through the relative responsiveness (rho) determined for histamine (Hist), oxytocin (Oxy) and acetylcholine (Ach) in prepuberal untreated, estrogen, and estrogen plus progesterone dominated uteri of mouse, it was possible to measure the capability of each receptor system, which mediates responses induced by these agonists. 2.

Evidence for multiple sources of calcium involved on the contractile effects of agonists in the dog uterus. Influence of ovarian sexual hormones.

We compared the characteristics of Ca2+ pools involved in the contractile effect of acetylcholine (Ach), histamine (Hist), oxytocin (Oxy) and barium (Ba2+) in prepuberal untreated or estrogen plus progesterone dominated uteri. After Ca2+ (0.2 mM) withdrawal different rates of decay for cited agonists were observed.

Differential sensitivity of major types of opioid binding sites to U.V. irradiation.

The three major types of opioid binding sites exhibited differential sensitivity to inactivation by ultraviolet irradiation. The order of sensitivity was delta greater than mu greater than kappa. Two separate rates of inactivation by U.

Influence of castration of the neonatal rat on the contractile effects of barium chloride and adrenaline in isolated vas deferens: the role of calcium.

Time-response curves to maximal concentrations of barium chloride (BaCl2) (3 X 10(-2) M) and adrenaline (10(-4) M) were studied in vasa deferentia from 3-month-old rats castrated at birth. Either barium or adrenaline was left in the organ baths for 5-min periods, at intervals of about 30 min, and the corresponding isotonic contractions recorded. Two types of effects were measured: the fade response (Jurkiewicz et al.

Inhibitory effects of ketamine on the isolated uteri of the rat: evidence for the mechanism of action.

The inhibitory effect of ketamine on the agonist-induced contraction of isolated rat uteri was compared with that of papaverine and verapamil. Under similar experimental conditions papaverine and verapamil were found to be more potent than ketamine. When preparations were preincubated for 20 min with either ketamine (3 X 10(-5) to 10(-3) M) or papaverine (10(-6) to 10(-5) M), a noncompetitive antagonism was observed against oxytocin with pD'2 values of 3.