Muscarinic cholinergic receptors in human infant forebrain: [3H]Quinuclidinyl benzilate binding in homogenates and quantitative autoradiography in sections

1985 ◽  
Vol 19 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Michael V. Johnston ◽  
Fayes S. Silverstein ◽  
Fredericko O. Reindel ◽  
John B. Penney ◽  
Anne B. Young
Keyword(s):  
Cholinergic Receptors ◽  
Quantitative Autoradiography ◽  
Human Infant ◽  
Muscarinic Cholinergic Receptors ◽  
Muscarinic Cholinergic ◽  
Quinuclidinyl Benzilate

Isolated parietal cells: [3H]QNB binding to putative cholinergic receptors

1980 ◽  
Vol 239 (3) ◽  
pp. G204-G209
Author(s):  
R. Ecknauer ◽  
W. J. Thompson ◽  
L. R. Johnson ◽  
G. C. Rosenfeld
Keyword(s):  
Specific Binding ◽  
Cholinergic Receptors ◽  
Parietal Cells ◽  
Cholinergic Antagonists ◽  
Single Population ◽  
Muscarinic Cholinergic Receptors ◽  
Cholinergic Antagonist ◽  
Muscarinic Cholinergic ◽  
Quinuclidinyl Benzilate

The tritiated muscarinic cholinergic antagonist quinuclidinyl benzilate, [3H]QNB, was used as a direct probe for the detection and characterization of muscarinic cholinergic receptors associated with the particulate fraction of isolated and purified rat gastric muscosal parietal cells. Specific binding is saturable (Bmax = 55 fmol/mg protein, KD = 0.78 nM), shows a single population of binding sites, and has appropriate pharmacological specificity. Nanomolar concentrations of muscarinic cholinergic antagonists, such as atropine and scopolamine, inhibit [3H]QNB binding by 50%, whereas micromolar concentrations are needed for agonists, such as acetylcholine, oxotremorine, and carbamylcholine. Binding is also stereoselective as shown by the more than 1,000-fold difference in inhibitory potencies of the stereoisomers of benzetimide. Noncholinergic agents, including pentagastrin, histamine, and the H2-receptor antagonists cimetidine and metiamide, have little or no effect on [3H]QNB binding at concentrations of 100 microM. These data support the existence of specific parietal cell muscarinic cholinergic receptors with which the secretagogue acetylcholine may directly interact to initiate gastric acid secretion.

Muscarinic Acetycholine Receptors of the Small Intestine and Pancreas of the Rat: Distribution and the Effect of Vagotomy

1982 ◽  
Vol 62 (2) ◽  
pp. 203-207 ◽  
Author(s):  
P. E. T. Isaacs ◽  
J. S. Whitehead ◽  
Y. S. Kim
Keyword(s):  
Small Intestine ◽  
Duodenal Mucosa ◽  
Cholinergic Receptors ◽  
Jejunal Mucosa ◽  
Ileal Mucosa ◽  
Muscarinic Cholinergic Receptors ◽  
Muscarinic Cholinergic ◽  
Small Intestinal ◽  
Mucosal Innervation ◽  
Quinuclidinyl Benzilate

1. The distribution of muscarinic cholinergic receptors (mAChR), detected by atropine-inhibitable binding of [3H]quinuclidinyl benzilate, was examined in membrane fractions of pancreas, small intestinal muscle, mucosa, villi and crypts of sham-operated and vagotomized rats. 2. Specific (atropine inhibitable) [3H]quinuclidinyl benzilate binding was greater to the ileal mucosa than to jejunal mucosa or to duodenal mucosa, but binding to crypt and villus fractions was not significantly different. This distribution of specific [3H]quinuclidinyl benzilate binding suggests that cholinergic mucosal innervation is more important in the ileum than the jejunum. 3. Vagotomy produced a decrease in the amount of specific [3H]quinuclidinyl benzilate binding to duodenal mucosa only, suggesting that parasympathetic denervation of the small intestine does not cause mucosal hypersensitivity to acetylcholine by an increase in mAChR.

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