A role for cyclic GMP in the initiation of cardiac pressor reflexes by bradykinin and capsaicin.

: Reflexogenic effects of bradykinin on the cardiac sympathetic afferents supplying the dog epicardium were inhibited by treatment of the heart surface with either methylene blue or the compound LY-83583 (6-anilino-5,8-quinolinedione), which are known to lower cellular levels of cyclic GMP. Stimulation of cyclic GMP production by epicardial treatment with the NO-containing synonimine compound, SIN-1, potentiated bradykinin-induced reflex effects. In contrast, the sympathetic cardiac pressor response induced by capsaicin was not influenced by epicardial treatment with either methylene blue, LY-83583 or SIN-1. These findings indicate the importance of cyclic GMP for the reflexogenic activity of bradykinin, but not that of capsaicin on the sympathetic afferents supplying the dog heart.