Effect of autonomic blocking agents on local cerebral blood flow in the rat.
The local effect of autonomic blocking agents on the resting cerebral blood flow of anaesthetized rats was investigated in 78 anatomical structures. The existence of an alpha-adrenergic vascular tone was indicated by the average flow increase of 28 +/- 3% and 17 +/- 3% after the administration of the alpha-receptor blocking agents phenoxybenzamine (56 mg/kg i.p.) and phentolamine (1 mg/kg i.v.), respectively. The injection of atropine (1 mg/kg i.v.) increased the average blood flow by 19 +/- 2%, whereas the overall effect of the beta-blocking agent propranolol (1 mg/kg i.v.) was statistically not significant. The magnitude of local blood flow changes in specific cerebral areas exhibited considerable variation in all experimental groups. The comparison of individual and overall flow changes suggests that some of the discrepancies among different investigations could have resulted from the intraindividual heterogeneity of evoked flow changes.
D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D008297:Male; D010643:Phenoxybenzamine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013565:Sympatholytics / Q000494:pharmacology*
D013565:Sympatholytics; D010643:Phenoxybenzamine; D001285:Atropine; D011433:Propranolol; D010646:Phentolamine