Disparate responses of blood pressure to adrenergic stimuli during beta blockade.
Insulin hypoglycemia or epinephrine release may lead to adverse increases in blood pressure in the presence of non-cardioselective beta-blockers. However, increases in blood pressure have not been observed in beta-blocker treated patients during physical exercise, handgrip tests, or during infusions with the alpha-adrenergic agonist, phenylephrine. In this study we have further evaluated the role of adrenergic stimuli in the etiology of these responses of blood pressure during beta-blocker therapy. These data do not support a direct role for beta 2 receptors or norepinephrine in pressor responses observed during beta-blocker therapy. Blockade of beta 1 receptors or, more likely, a facilitating effect of propranolol upon the alpha-adrenergic receptors might explain the enhanced pressor responses found after administration of the alpha-adrenergic agonist, phenylephrine. However, high doses of phenylephrine seem needed to elicit such pressor responses.
Drayer
J I
JI
Weber
M A
MA
Frankfort
P P
PP
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002078:Butoxamine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D012083:Renin / Q000097:blood; D013564:Sympathetic Nervous System / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D007328:Insulin; D002078:Butoxamine; D010656:Phenylephrine; D011433:Propranolol; D012083:Renin; D006854:Hydrocortisone; D009638:Norepinephrine