EFFECT OF ACETYLSALICYLIC ACID AND MORPHINE ON PRESSOR RESPONSES PRODUCED BY BRADYKININ

Biphasic or pressor responses are produced by the intravenous or intra-carotid injection of bradykinin in anaesthetized cats and in conscious or anaesthetized dogs. The analgesic drugs, acetylsalicylic acid and morphine, failed to abolish or even reduce consistently the pressor responses to bradykinin. These findings indicate that whereas a reflex response to pain caused by the intra-carotid injection of bradykinin may partially contribute to the pressor phase, especially in the conscious dog, this mechanism cannot be wholly responsible. It is concluded that bradykinin has a direct action in the central nervous system which leads to an increase in sympathetic cardiovascular tone. © 1969.