Vascular and sympathoadrenal responses to bradykinin and a bradykinin analogue.
These experiments were designed to assess the interaction of bradykinin and its antagonist (Arg-Pro-Hyp-Gly-Phe-Ser-DPhe-Phe-Arg-trifluoroacetic acid) with the sympathoadrenal system. Three groups of male Wistar rats received 5-minute intra-arterial infusions of either dextrose (Group 1, n = 6), bradykinin, 250 micrograms/min (Group 2, n = 5), or bradykinin, 25 micrograms/min (Group 3, n = 4). Six other groups received a similar infusion of the bradykinin antagonist at 250 micrograms/min. They were either intact rats (Group 4, n = 10) or rats previously submitted to chemical sympathectomy (Group 5, n = 17), to adrenal enucleation (Group 6, n = 8), to combined alpha-adrenergic and beta-adrenergic blockade (Group 7, n = 7), to alpha 1-adrenergic receptor blockade (Group 8, n = 8), or to alpha 2-adrenergic receptor blockade (Group 9, n = 8). Bradykinin infusion produced a sustained fall in mean arterial pressure (MAP) in Groups 2 and 3 (by -48 +/- 3 and -36 +/- 7 mm Hg, respectively) associated with similar increases in plasma epinephrine levels (100-fold), and norepinephrine (sevenfold) as compared with Group 1. The bradykinin antagonist infusion in intact rats produced a 23 +/- 4 mm Hg rise in MAP associated with a sixfold increase in epinephrine and a twofold increase in norepinephrine. Group 5 rats with lower baseline catecholamine levels had an even larger MAP rise (30 +/- 6 mm Hg) accompanied by a rise in epinephrine and norepinephrine proportionally similar to that of intact animals.(ABSTRACT TRUNCATED AT 250 WORDS)
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001920:Bradykinin / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004347:Drug Interactions; D004837:Epinephrine / Q000097:blood; D005463:Fluoroacetates; D006339:Heart Rate / Q000187:drug effects*; D007269:Injections, Intra-Arterial; D008297:Male; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D005463:Fluoroacetates; C052791:B 3852; D001920:Bradykinin; D009638:Norepinephrine; D004837:Epinephrine