Linked Life Data

1851449

Source:http://linkedlifedata.com/resource/pubmed/id/1851449

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-6-19
pubmed:abstractText
The interaction between alpha 2- and beta-adrenergic receptors was investigated in rat cerebral cortical membranes. Clonidine inhibition of [3H]dihydroalprenolol ([3H]DHA) binding resulted in biphasic competition curves with a mean Hill coefficient of 0.45. The addition of 1 microM yohimbine caused a rightward shift of the first portion of the clonidine inhibition curve. In the presence of 1 microM clonidine, the maximum concentration which did not inhibit [3H]DHA binding, inhibition curves of [3H]DHA binding by isoproterenol shifted to the right. A mean Hill coefficient increased from a control value of 0.63 to 0.76. Computer modeling analysis revealed that 1 microM clonidine decreased a beta-adrenergic high-affinity state from 28% to 13%. However, the addition of 1 microM yohimbine completely prevented the clonidine-induced reduction in the beta-adrenergic high-affinity state. In the presence of 200 microM GTP, the effect of clonidine was not observed. In addition, Kd and Bmax values for [3H]p-aminoclonidine ([3H]PAC) binding were not significantly changed by the addition of 100 nM isoproterenol, the maximum concentration which did not inhibit [3H]PAC binding. Moreover, isoproterenol inhibition of [3H]PAC binding resulted in steep competition curves with a mean Hill coefficient of 0.97. The addition of 1 microM alprenolol did not affect the isoproterenol inhibition curve. These data demonstrated that clonidine caused a decrease in agonist and antagonist affinity for beta-adrenergic receptors, while isoproterenol did not modulate the binding characteristics of alpha 2-adrenergic receptors. Furthermore, these results suggest that regulation between alpha 2- and beta-adrenergic receptors is not bidirectional, but is instead unidirectional from alpha 2-adrenergic receptors to beta-adrenergic receptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
542
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
181-6
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Interaction between alpha 2- and beta-adrenergic receptors in rat cerebral cortical membranes: clonidine-induced reduction in agonist and antagonist affinity for beta-adrenergic receptors.
pubmed:affiliation
Department of Psychiatry, Mie University School of Medicine, Japan.
pubmed:publicationType
Journal Article