title: In vivo modulation of the number of muscarinic receptors in rat brain by cholinergic ligands.
abstract: Administration of the muscarinic agonist oxotremorine led to a decrease in the number of muscarinic receptors, as determined by specific binding of [3H]quinuclidinyl benzilate ([3H]QNB), in several rat brain regions both during development and at maturity. In contrast, administration of the muscarinic antagonist scopolamine led to an increase in the number of [3H]QNB-binding sites in various brain regions. Scopolamine also prevented the decrease in the number of [3H]QNB-binding sites induced by administration of an organophosphorus drug. The results are compatible with the hypothesis that the number of brain muscarinic receptors, or at least of a sub-class of them, is regulated by their transmitter.
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D008024:Ligands; D008297:Male; D009946:Organothiophosphorus Compounds / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000187:drug effects*; D011976:Receptors, Muscarinic / Q000032:analysis / Q000187:drug effects*; D012601:Scopolamine / Q000494:pharmacology*
chemical_list: D008024:Ligands; D009946:Organothiophosphorus Compounds; D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; D010095:Oxotremorine; D011813:Quinuclidinyl Benzilate; C003415:amiton; D012601:Scopolamine; D000110:Acetylcholinesterase