Relaxation of depolarized guinea pig taenia caecum induced by some antispasmodics.

Taenia isolated from the guinea pig caecum were used for the experiments. No inhibitory response of the depolarized taenia to isoprenaline was observed during the significant increase of cyclic AMP level. These observations suggest that the total tissue level of cyclic AMP is not an important determinant of relaxation in the depolarized taenia. Antispasmodics, such as papaverine, benactyzine and Aspaminol (1,1-diphenyl-3-piperidino-butanol hydrochloride) relaxed the depolarized taenia, while the depolarized taenia was not relaxed by concentrations of dibutyryl cyclic AMP sufficient to relax the polarized taenia. Ca uptake by the depolarized taenia was inhibited by papaverine, benactyzine and Aspaminol but not by isoprenaline and dibutyryl cyclic AMP. These results indicate that relaxation of the depolarized taenia induced by the antispasmodics used was mainly due to inhibition of Ca uptake.