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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
|
| pubmed:dateCreated |
1982-3-22
|
| pubmed:abstractText |
(+/-)[125Iodo] cyanopindolol (ICYP) is a radioligand which binds with an extraordinarily high affinity and specificity to beta-adrenoceptors. In contrast to (+/-) [125Ido]-hydroxybenzylpindolol (IHYP), the new ligand has neither affinity to alpha-nor to 5-HT-receptors. The dissociation constants of ICYP for beta- adrenoceptors in various tissues range from 27 to 40 pM, thereby exceeding the affinity of IHYP by a factor of approximately 3. ICYP does not discriminate between beta 1- and beta 2-adrenoceptors. Therefore, the densities of the two receptor subtypes can be determined from competition curves of ICYP by drugs previously found to show in vitro selectivity for beta 1-adrenoceptors. The guinea pig left ventricle contains only beta 1-adrenoceptors, whereas in a lung tissue, the ratio of beta 1-to beta 2-adrenoceptors is 1 to 4. The calculated affinities of five beta 1-selective antagonists for beta 1-adrenoceptors were nearly identical in the ventricle and the lung. Kinetic studies of ICYP binding to guinea pig lung membranes indicated that the dissociation reaction consists of two components, a fast process (t 1/2 = 9 min) and a slower process (t 1/2 = 8.8 h). A mathematical treatment revealed two possibilities of interpretation: 1. Two forms of the receptor exist which are interconvertible. 2. The (+)- and (-)- enantiomers of ICYP dissociate with different rate constants. The low dissociation constant of ICYP in combination with its high specific radioactivity (2175 Ci mmole -1) allows binding studies to be carried out with small protein and ligand concentrations, e.g. 3 microgram protein per assay in guinea pig lung membranes.
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adrenergic beta-Antagonists,
http://linkedlifedata.com/resource/pubmed/chemical/Iodocyanopindolol,
http://linkedlifedata.com/resource/pubmed/chemical/Ligands,
http://linkedlifedata.com/resource/pubmed/chemical/Pindolol,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Adrenergic, beta,
http://linkedlifedata.com/resource/pubmed/chemical/iodohydroxybenzylpindolol
|
| pubmed:status |
MEDLINE
|
| pubmed:issn |
0028-1298
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
317
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
277-85
|
| pubmed:dateRevised |
2003-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:6119625-Adrenergic beta-Antagonists,
pubmed-meshheading:6119625-Animals,
pubmed-meshheading:6119625-Cerebral Cortex,
pubmed-meshheading:6119625-Computers,
pubmed-meshheading:6119625-Guinea Pigs,
pubmed-meshheading:6119625-Iodocyanopindolol,
pubmed-meshheading:6119625-Kinetics,
pubmed-meshheading:6119625-Ligands,
pubmed-meshheading:6119625-Lipolysis,
pubmed-meshheading:6119625-Lung,
pubmed-meshheading:6119625-Male,
pubmed-meshheading:6119625-Models, Chemical,
pubmed-meshheading:6119625-Myocardium,
pubmed-meshheading:6119625-Pindolol,
pubmed-meshheading:6119625-Rats,
pubmed-meshheading:6119625-Receptors, Adrenergic,
pubmed-meshheading:6119625-Receptors, Adrenergic, beta,
pubmed-meshheading:6119625-Stereoisomerism
|
| pubmed:year |
1981
|
| pubmed:articleTitle |
(+/-)[125Iodo] cyanopindolol, a new ligand for beta-adrenoceptors: identification and quantitation of subclasses of beta-adrenoceptors in guinea pig.
|
| pubmed:publicationType |
Journal Article
|