Direct labeling of rat M3-muscarinic receptors by [3H]4DAMP.
The muscarinic receptors of rat submaxillary gland, rat heart and rat cortex were directly labeled using the ligand [3H]4-diphenylacetoxy-N-methyl-piperidine methiodide [( 3H]4DAMP). In the rat submaxillary gland, [3H]4DAMP predominantly bound with high affinity (Kd = 0.2 nM) to a population of binding sites that displayed the pharmacology of the M3 muscarinic receptor subtype. In rat heart, [3H]4DAMP labeled the M2 muscarinic receptor with low affinity (Kd = 4 nM). In rat cortex [3H]4DAMP predominantly bound to a population of sites with high affinity (Kd = 0.2 nM). The pharmacology of these sites was consistent with [3H]4DAMP labeling both M1 and M3 muscarinic receptors present in rat cortex with high affinity. These data indicate that [3H]4DAMP represents a useful ligand for selectively labeling the M1 and M3 muscarinic receptor subtypes.
Michel
A D
AD
Department of Neuropharmacology, Glaxo Group Research, Ltd., Ware, Hertfordshire U.K.
Stefanich
E
E
Whiting
R L
RL
D000218:Adamantane / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D008024:Ligands; D019832:N-Methylscopolamine; D010890:Pirenzepine / Q000031:analogs & derivatives / Q000494:pharmacology; D011506:Proteins / Q000032:analysis / Q000378:metabolism; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects*; D012602:Scopolamine Derivatives / Q000494:pharmacology; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism
D008024:Ligands; D011506:Proteins; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; C016358:2,4-diamino-5-adamantyl-6-methylpyrimidine; D010890:Pirenzepine; C048593:otenzepad; D000218:Adamantane; D019832:N-Methylscopolamine