Linked Life Data

7722621

Source:http://linkedlifedata.com/resource/pubmed/id/7722621

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1995-5-25
pubmed:abstractText
Inhibitory effects of GABA on K(+)-evoked Ca2+ influx into rat retinal bipolar cell terminals were studied using calcium imaging methods. Application of high K+ evokes a sustained, reversible increase in [Ca2+]i at bipolar cell terminals, which occurs mainly via dihydropyridine-sensitive (L-type) Ca2+ channels. There are at least two GABA receptor subtypes coexisting at bipolar cell terminals: a conventional GABAA receptor and a bicuculline/baclofen-insensitive GABA receptor. Activation of either GABA receptor inhibited the K(+)-evoked Ca2+ response. However, these two GABA receptor subtypes have distinct properties. GABAA receptors suppress the Ca2+ response only at relatively high concentrations of agonist, and with fas kinetics and a narrow dynamic range. In contrast, the bicuculline/baclofen-insensitive GABA receptors produce inhibition on the Ca2+ response at a much lower concentration of agonist, and with slow onset and a wider dynamic range. The pharmacologic profile of the bicuculline/baclofen-insensitive GABA receptor at bipolar cell terminals is most similar to the GABAC receptor reported by Feigenspan et al. (1993). Unlike the GABAC receptors described in other species, it is extremely insensitive to picrotoxin. Therefore, it may be appropriate to refer to this receptor as a picrotoxin-insensitive GABAc receptor. 3-Aminopropyl(methyl)phosphinic acid (3-APMPA) and 3-aminopropylphosphonic (3-APA), two phosphate analogs of GABA, selectively antagonize the picrotoxin-insensitive GABAc receptors but not the GABAA receptors in this system. These results imply a functional role for multiple GABA receptors in regulating synaptic transmission at bipolar cell terminals.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/3-aminopropyl(methyl)phosphinic acid, http://linkedlifedata.com/resource/pubmed/chemical/Baclofen, http://linkedlifedata.com/resource/pubmed/chemical/Bicuculline, http://linkedlifedata.com/resource/pubmed/chemical/Calcium, http://linkedlifedata.com/resource/pubmed/chemical/GABA-C receptor, http://linkedlifedata.com/resource/pubmed/chemical/Organophosphorus Compounds, http://linkedlifedata.com/resource/pubmed/chemical/Picrotoxin, http://linkedlifedata.com/resource/pubmed/chemical/Potassium, http://linkedlifedata.com/resource/pubmed/chemical/Propylamines, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, GABA, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, GABA-A, http://linkedlifedata.com/resource/pubmed/chemical/aminopropylphosphonate, http://linkedlifedata.com/resource/pubmed/chemical/gamma-Aminobutyric Acid
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2668-79
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Multiple GABA receptor subtypes mediate inhibition of calcium influx at rat retinal bipolar cell terminals.
pubmed:affiliation
Department of Neurology, Children's Hospital, Boston, Massachusetts, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't