Takao Yanagawa

[Effects of orciprenaline on the responses to Ca, K, acetylcholine and Ba in the isolated seminal vesicles of guinea pigs, especially in relation to cyclic AMP (author's transl)].

By using the isolated seminal vesicles of guinea pigs, the effects of dibutyryl cyclic AMP and beta-stimulant, orciprenaline, on the responses to Ca, K, acetylcholine and Ba were investigated, especially in relation to cyclic AMP. The following results were obtained. 1. Orciprenaline inhibited the contraction produced by Ca, K, acetylcholine and Ba in a dose-dependent manner, and the inhibition became larger in the order of Ca, K, acetylcholine and Ba. 2. Dibutyryl cyclic AMP showed the same results as those of orciprenaline. That is, dibutyryl cyclic AMP inhibited the contractions produced by acetylcholine and Ba. 3. Orciprenaline showed the increased level of cyclic AMP in a dose-dependent manner. But the increase was not remarkable in the concentration in which the contractions produced by the tested contractile agents were inhibited by about 50%. From these results, the following suggestions were obtained; (1) there exists beta-receptor in guinea pig seminal vesicles and (2) a part of actions of orciprenaline is due to a mechanism unrelated to cyclic AMP.