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Title: Influence of endogenous norepinephrine on cerebral blood flow and metabolism. Author: MacKenzie ET, McCulloch J, Harper AM. Journal: Am J Physiol; 1976 Aug; 231(2):489-94. PubMed ID: 961902. Abstract: The influence of brain norepinephrine on cerebral metabolism and blood flow was examined because exogenous norepinephrine, administered in a way that the blood-brain barrier is bypassed, has been shown to effect pronounced changes in the cerebral circulation. Reserpine (40 mug/kg, by intracarotid infusion) was administered in order to release brain norepinephrine in five anesthetized baboons. Reserpine significantly increased cerebral oxygen consumption (23%) and cerebral blood flow (50%). This response lasted for approximately 60 min. In a further five animals, effects of central beta-adrenoreceptor blockade were studied. Pro pranolol (12 mug/kg-min) produced an immediate, significant reduction in both cerebral oxygen consumption (40%) and cerebral glucose uptake (39%). Cerebral blood flow was reduced minimally. However, the responsiveness of the cerebral circulation to induced hypercapnia was severely attenuated from a gradient of 3.22 before, to 1,11 after, administration. These experiments suggest that central norepinephrine can influence the cerebral circulation primarily through noradrenergic effects on brain metabolism.[Abstract] [Full Text] [Related] [New Search]