ISSN:
1573-2568
Keywords:
stomach
;
human gastric mucosa
;
muscarinic receptor subtype
;
acid secretion
;
glandular M3 receptor
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Five subtypes of muscarinic receptors have been distinguished by pharmacological and molecular biological methods. This report characterizes the muscarinic subtype present in human gastric mucosa by radioligand binding studies. The receptor density was 27 ±6 fmollmg protein and the tritiated ligand N-methylscopolamine had an affinity of (KD)0.39±0.08 nM (n=11). The M1 receptor selective antagonist pirenzepine and the M2 receptor selective ligand AF-DX 116 had low affinities of 148±32 nM (n=13) and 4043±1011 nM (n=3) KD,respectively. The glandular M3 antagonists hexahydrosiladifenidol and silahexocyclium had high affinities of KD 78±23 nM (n=5) and 5.6±1.8 nM (n=3). The agonist carbachol interacted with a single low-affinity site and binding was insensitive to modulation by guanine nucleotides. Antagonist and agonist binding studies thus showed an affinity profile typical of M3 receptors of the glandular type.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01540563
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