Linked Life Data

8051693

Source:http://linkedlifedata.com/resource/pubmed/id/8051693

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-9-8
pubmed:abstractText
The effects of G-protein activation were investigated on tonic, large depolarization-induced Ca2+ channel facilitation in cultured bovine adrenal chromaffin cells. Under whole-cell voltage clamp, activation of G proteins by intracellular dialysis with 200 microM GTP-gamma S did not significantly affect prepulse facilitation or whole-cell Ba2+ current (IBa) density. In contrast, inactivation of G proteins by intracellular GDP-beta S or pertussis toxin (PTX) pretreatment completely abolished or markedly attenuated facilitation of IBa, respectively. GDP-beta S dialysis resulted in nearly a threefold increase in peak IBa density, whereas PTX pretreatment resulted in a 50% increase. Our results indicate that under control recording conditions (200 microM intracellular GTP), G proteins are tonically activated and suppress high-voltage-activated (HVA) Ca2+ channels in a voltage-dependent and voltage-independent manner. Local superfusion of chromaffin cells with normal bath solution produced a rapid and reversible increase (approximately 50%) in IBa amplitudes that also abolished prepulse facilitation. Together, these results demonstrate that tonic facilitation of HVA Ca2+ channels in bovine chromaffin cells involves the voltage-dependent relief of a G-protein-mediated suppression, imposed by chromaffin cell secretory products that feedback and activate G-protein-coupled autoreceptors.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-2631
pubmed:author
pubmed:issnType
Print
pubmed:volume
140
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
47-56
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
G-protein activation mediates prepulse facilitation of Ca2+ channel currents in bovine chromaffin cells.
pubmed:affiliation
Department of Physiology and Biophysics, University of Cincinnati College of Medicine, Ohio 45267-0576.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't