Studies on the Pressor Responses Produced by Bradykinin and Kallidin

The hypotensive effect of bradykinin was first described by Rocha e Silva, Beraldo & Rosenfeld (1949), and has been found in all mammals so far investigated (StUrmer & Cerletti, 1961; Schroder & Hempel, 1964). A number of studies, however, have shown that bradykinin may also increase the blood pressure, or cause a biphasic response. Thus, Croxatto, Belmar, Pereda & Labarca (1962) reported a hypertensive effect of bradykinin in rats with low blood pressure, and Lecomte, Troquet & Cession-Fossion (1964) described biphasic responses in rats and rabbits after repeated administration of bradykinin. Using cross-circulation techniques in dogs, it was shown by Benetato, Haulica, Muscalu, Bubuianu & Galesanu (1964) that intra-cranial administration of bradykinin produced a biphasic response. A rise in blood pressure has also been described when bradykinin is injected intra-arterially to various organs, including the brain, in cats and dogs. It was considered to be a reflex component of the "pseudo- affective" response to pain (Guzman, Braun & Lim, 1962).