“Graded concentrations of salbutamol, isoproterenol , papaverine, theophylline, thioglycollate, and MgCl2 produced a decrease in the maximal effect of oxytocin and a shift of the concentration-effect curves to the right.”
“Salbutamol and isoproterenol appeared to act as functional antagonists of oxytocin in which agonist and antagonist each interacted with its own specific receptor to produce a decreased combined effect on a common effector.”