title: Differential down-regulation by carbamylcholine of putative nicotinic and muscarinic acetylcholine receptor sites in chick retina cultures.
abstract: The effect of chronic exposure to the cholinergic against carbamycholine on the number of nicotinic and muscarinic cholinergic ligand binding sites in primary cultures of chick embryo retina has been investigated. Within 24 h, 1 mM carbamylcholine led to a 60-70% loss of specific binding sites for the muscarinic antagonist [3H] quinuclidinylbenzilate, whereas the binding of the nicotinic cholinergic ligand [125I] alpha-bungarotoxin remained almost unchanged under the same conditions. The reduction in muscarinic cholinergic ligand binding sites by carbamylcholine was blocked by atropine and scopolamine, but not affected by the inhibition of protein synthesis or the removal of extracellular calcium. These data indicate a different metabolic regulation by agonist occupancy of putative nicotinic and muscarinic acetylcholine receptors in the chick central nervous system.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D002478:Cells, Cultured; D002645:Chickens; D003513:Cycloheximide / Q000494:pharmacology; D011950:Receptors, Cholinergic / Q000032:analysis*; D011976:Receptors, Muscarinic / Q000032:analysis*; D011978:Receptors, Nicotinic / Q000032:analysis*; D012160:Retina / Q000032:analysis*; D012601:Scopolamine / Q000494:pharmacology
chemical_list: D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D001285:Atropine; D002217:Carbachol; D003513:Cycloheximide; D012601:Scopolamine; D002118:Calcium