Linked Life Data

7252842

Source:http://linkedlifedata.com/resource/pubmed/id/7252842

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1981-9-25
pubmed:abstractText
Physiological evidence suggests that muscarinic receptors mediate the secretory response of the intestinal mucosa of cholinergic agonists, but the question of whether muscarinic receptors are intrinsic to intestinal epithelial cells has remained unanswered. We therefore studied binding of the muscarinic ligand [3H]quinuclidinyl benzilate to isolated rat colonic epithelial cells. Specific binding in the membrane preparation reached equilibrium in 30 min at 37 degrees C, was linear with tissue protein concentration and was saturable. Estimates of the apparent equilibrium dissociation constant (KD) equalling 0.11 +/- 0.03 nM and of maximum receptor density (Bmax) equalling 103.6 +/- 9.0 fmol/mg of protein were determined from Scatchard plots of the binding data. The Hill coefficient for binding was 0.93 +/- 0.04. From kinetic analysis of data, association and dissociation rate constants of 8.6 X 10(7) M-1 min-1 and 6.0 X 10(-3) min-1, respectively, were calculated. Inhibition of specific binding was stereoselective and pharmacologically specific for muscarinic agents. Specific binding, vasoactive intestinal peptide-stimulated adenylate cyclase and Na+-K+-stimulated adenosine triphosphatase activities were highest in a mitochondrial-free fraction of rat colonocytes. Specific binding was lowest in the nuclear fraction, followed by the total particulate and mitochondrial fractions. The regional distribution of specific binding along the length of the intestine was also studied. Scatchard analysis revealed one specific binding site, with the same KD in the jejunum, ileum and colon. The receptor density was the same in the jejunum and ileum, but about 5-fold higher for the existence of muscarinic receptors on intestinal epithelial cells and suggest that the effects of muscarinic drugs on intestinal epithelial cell function are mediated by interaction with these receptors.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
218
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
426-34
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
Evidence for muscarinic receptors on rat colonic epithelial cells: binding of [3H]quinuclidinyl benzilate.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't