title: Modulation of rat brain alpha- and beta-adrenergic receptor populations by lesion of the dorsal noradrenergic bundle.
abstract: Bilateral lesion of the ascending noradrenergic fibers in the dorsal bundle of adult Wistar rats with 4 micrograms 6-hydroxydopamine caused extensive depletion of norepinephrine in all forebrain areas, but led to a 54% increase in norepinephrine levels in the cerebellum. beta-Adrenergic receptor binding of [3H]dihydroalprenolol was significantly increased in all forebrain areas depleted of norepinephrine except hypothalamus. The increase in [3H]dihydroalprenolol binding was due to 62% and 34% increases in the number of beta-receptor sites in the frontal cerebral cortex and hippocampus respectively. Binding of [3H]WB-4101 to alpha 1-adrenergic receptors after dorsal bundle lesion was augmented generally to a lesser extent than beta-receptor binding, with significantly increased numbers of sites only in the frontal cortex (74%), thalamus (20%) and septum. Both alpha 1- and beta-receptor binding sites were reduced in number by 25-28% in the cerebellum of dorsal bundle-lesioned rats, whereas intraventricular administration of 6-hydroxydopamine to adult rats, which depletes norepinephrine in the cerebellum by 96%, increased cerebellar alpha 1- and beta-receptor binding by 33-40%. Binding of [3H]clonidine to forebrain alpha 2-adrenergic receptors was significantly elevated in the frontal cortex, but reduced in the amygdala and septum, after dorsal bundle lesion.
mesh_terms: D000679:Amygdala / Q000378:metabolism; D000818:Animals; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D003000:Clonidine / Q000378:metabolism; D004082:Dihydroalprenolol / Q000378:metabolism; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D006892:Hydroxydopamines / Q000494:pharmacology; D008125:Locus Coeruleus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D009434:Neural Pathways / Q000187:drug effects; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000378:metabolism
chemical_list: D006892:Hydroxydopamines; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D003000:Clonidine; D009638:Norepinephrine