Effects of adrenergic blockade on plasma catecholamine levels during adrenaline infusion.
Alpha and beta adrenergic blocking drugs were administered, either singly or in combination, prior to a 3hr adrenaline infusion (2 microgram kg body wt-1 min-1)), Animals were premediated with either phenoxybenzamine (1 mg kg body wt-1 min-1). Phenoxybenzamine did not affect circulating adrenaline levels, but propranolol, either alone or in combination with phenoxybenzamine, resulted in a significant reduction in plasma adrenaline levels when compared with the control unblocked situation of adrenaline infusion without premedication. The results provide a possible explanation for the protective effect of combined adrenergic blockade in shock situations.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000378:metabolism*; D005260:Female; D007263:Infusions, Parenteral; D009638:Norepinephrine / Q000097:blood*; D010643:Phenoxybenzamine / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*; D011674:Pulse / Q000187:drug effects; D012119:Respiration / Q000187:drug effects; D012756:Sheep
D010643:Phenoxybenzamine; D011433:Propranolol; D009638:Norepinephrine; D004837:Epinephrine