Linked Life Data

3941394

Source:http://linkedlifedata.com/resource/pubmed/id/3941394

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1986-2-20
pubmed:abstractText
The effects of neuromuscular blocking drugs and muscarinic agonists and antagonists on the dissociation of [3H]quinuclidinylbenzilate ([3H]QNB) from muscarinic receptors was studied on rat atrial homogenates. In typical experiments the investigated drug was added to the homogenate equilibrated with [3H]QNB and the amount of undissociated [3H]QNB receptor complexes was measured 40 min later. The antagonists atropine and pirenzepine, agonists carbamoylcholine and methylfurmethide and neuromuscular blockers pancuronium, d-tubocurarine and decamethonium caused a concentration-dependent dissociation of [3H]QNB from the receptors, which may be explained by their competition with [3H]QNB for the same (primary) binding sites. In accordance with this, these drugs did not affect the dissociation of [3H]QNB elicited by an excess of atropine, which indicates that the kinetics of dissociation of the [3H]QNB receptor complex remained unchanged in their presence. Neuromuscular blockers alcuronium, gallamine and to a lesser degree tercuronium differed from the other drugs in that 1) their effect on [3H]QNB dissociation was biphasic, being higher at their low (10(-6) to 10(-5) M) than at their high concentrations (10(-4) to 10(-3) and that 2) at high concentrations they strongly inhibited the dissociation of [3H]QNB receptor complexes elicited by the excess of atropine. Their behavior may be rationalized by assuming that at low concentrations they bind to the primary binding site making rebinding of once dissociated [3H]QNB molecules improbable (competitive mechanism), whereas at high concentrations they also act on a secondary (allosteric) binding site stabilizing the [3H]QNB receptor complexes by slowing their off-kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
236
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
219-23
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Stabilization of antagonist binding to cardiac muscarinic acetylcholine receptors by gallamine and other neuromuscular blocking drugs.
pubmed:publicationType
Journal Article, In Vitro