Increase in beta- and alpha 1-adrenoceptor binding sites in the rat brain and in the alpha 1-adrenoceptor functional sensitivity after the DSP-4-induced noradrenergic denervation.
Changes in the density of beta- and alpha 1-adrenoceptors were studied following denervation of the rat cerebral cortex and hippocampus, caused by systemic administration of DSP-4. The noradrenergic denervation increased both beta- and alpha 1-adrenoceptor density by about 30 and 17%, respectively in the cortex, and by about 30% in the hippocampus. In order to estimate the behavioral response of normal and DSP-4-treated rats to alpha 1-agonist, the influence of phenylephrine (25 micrograms ICV) on the exploratory activity of rats in the open field was measured. Phenylephrine failed to change the exploratory activity of normal rats, but significantly increased it in DSP-4 animals. The results indicate that noradrenergic denervation produces an increase in number of both beta- and alpha 1-adrenoceptors and the functional supersensitivity to the alpha 1-adrenergic agonists.
D000818:Animals; D001596:Benzylamines / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000378:metabolism*; D003714:Denervation; D005106:Exploratory Behavior / Q000187:drug effects*; D006624:Hippocampus / Q000378:metabolism*; D007276:Injections, Intraventricular; D008297:Male; D009638:Norepinephrine / Q000502:physiology; D010656:Phenylephrine / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D001596:Benzylamines; D010880:Piperidines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; C015613:4-(5,6-dimethyl-2-benzofuranyl)piperidine; C012102:DSP 4; D009638:Norepinephrine