Bradykinin antagonism and prostaglandins in blood pressure regulation.
These experiments were designed to analyze the interaction of a bradykinin antagonist with prostaglandins in blood pressure regulation of normotensive rats. Male Wistar rats, divided into three groups, received a 5-minute intra-arterial infusion of the bradykinin antagonist [( DArgo-Hyp3-Thi5,8-DPhe7]BK-TFA) at 250 micrograms/min. Groups were either intact rats (group I, n = 5), pretreated with indomethacin (group II, n = 10), or pretreated with both indomethacin and prazosin (group III, n = 8). The bradykinin antagonist infusion, which was shown to inhibit exogenous bradykinin by greater than 76% in intact animals, did not alter mean arterial pressure in group I rats despite a twofold increase in norepinephrine and a threefold increase in epinephrine. Group II rats presented a progressive increase in mean arterial pressure during the bradykinin antagonist infusion (14 +/- 3 mm Hg), with no statistically significant change in plasma catecholamines. Group III, with lower baseline mean arterial pressure due to alpha 1-adrenergic blockade, had an increase in mean arterial pressure comparable with group II during bradykinin antagonist infusion (22 +/- 5 mm Hg), confirming that this response was not sympathetically mediated. We conclude that in normotensive rats bradykinin plays a role in blood pressure regulation that is closely linked to that of prostaglandins and that points to a balance between these systems.
Mulinari
R
R
Department of Medicine, Boston City Hospital, Massachusetts.
Gavras
I
I
Franco
R
R
Gavras
H
H
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure; D001920:Bradykinin / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors; D006339:Heart Rate / Q000187:drug effects; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D011224:Prazosin / Q000494:pharmacology; D011453:Prostaglandins / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D000317:Adrenergic alpha-Antagonists; D016861:Cyclooxygenase Inhibitors; D011453:Prostaglandins; C053748:B 4162; D001920:Bradykinin; D011224:Prazosin; D007213:Indomethacin