Adaptive effect and withdrawal syndrome of propranolol in relation to norepinephrine and epinephrine
Abstract
Two distinct phases of changes in the urinary and myocardial norepinephrine (NE) were observed in rats after sc injection of propranolol * 7d. The first phase was up-regulation of NE. The second phase was down-regulation of NE and designated as an adaptive effect which may be related to its antihypertensive effect. No adaptive effect on urinary E during medication was found. After withdrawal there was a significant rebound in NE and E, which might be the cause to lead to coronary accident in patients with severe ischaemic heart disease by acting on the hypersensitive beta-receptor in myocardium.
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