Muscarinic receptors in rat nasal mucosa are predominantly of the low affinity agonist type.
Specific [3H]l-quinuclidinyl benzilate binding to rat nasal mucosa homogenates occurs to a homogeneous class of binding sites with Kd = 60 +/- 2 10(-12) M and Bmax = 8.1 +/- 2 pmol/g tissue. Binding is stereoselectively inhibited by benzetimide enantiomers. Pirenzepine inhibits [3H]l-quinuclidinyl benzilate binding with low affinity (Ki = 5.0 10(-7) M), classifying the binding sites as muscarinic M2-receptors. Methylfurtrethonium and methacholine inhibit [3H]l-quinuclidinyl benzilate binding following an almost sigmoid curve at high concentrations pointing to the presence of mainly low affinity agonist binding sites.
D000818:Animals; D001570:Benzodiazepinones; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008688:Methacholine Compounds; D009116:Muscarine / Q000031:analogs & derivatives; D009297:Nasal Mucosa / Q000378:metabolism*; D010890:Pirenzepine; D011813:Quinuclidinyl Benzilate; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000378:metabolism*; D013237:Stereoisomerism
D001570:Benzodiazepinones; D008688:Methacholine Compounds; D011976:Receptors, Muscarinic; C008446:5-methylfurtrethonium; D010890:Pirenzepine; D011813:Quinuclidinyl Benzilate; D009116:Muscarine