DIFFERENT ACTIONS OF SOME RELAXANT AGENTS ACTING VIA THE CAMP SYSTEM IN RAT UTERUS

The influence of propranolol, isoprenaline, papaverine and caffeine on basal tone and contractile responses to spasmogens (oxytocin, KCl) wa s investigated in the presence and the absence of external calcium in estrogen-treated rat uterus. Isoprenaline, papaverine and caffeine rel axed precontracted uterus and caffeine also decreased the basal tone o f uterine muscle in calcium-containing or calcium-free solution. Propr anolol had a dual activity in calcium-free medium: lower concentration s contracted the sustained contraction elicited by oxytocin, whereas t he highest concentration partially relaxed it. In calcium-containing s olution the highest dose of propranolol partially inhibited KCl-induce d contractions.