The effect of catecholamine depletion on the bradykinin-induced relaxation of isolated smooth muscle.

The effect of depletion of catecholamines by tyramine or reserpine on the bradykinin-induced relaxation of the rat duodenum aan rabbit ileum was the object of this study. The relaxation was not affected by catecholamine depletion due to repeated addition of tyramine to the isolated organs from either normal or reserpine-treated animals. From these findings and on the basis of other data in the literature it can be concluded that the bradykinin relaxation is not due to a release of catecholamines, but rather to a direct effect on the smooth muscle cells.