Linked Life Data

9310436

Source:http://linkedlifedata.com/resource/pubmed/id/9310436

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1997-11-6
pubmed:abstractText
Olfactory bulb mitral cells express group I (mGluR1), group II (mGluR2), and group III (mGluR7 and mGluR8) metabotropic glutamate receptors. We examined the role of these mGluRs on excitatory synaptic transmission in cultured mitral cells with the use of whole cell patch-clamp recordings. The effects of group-selective mGluR agonists and antagonists were tested on alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-receptor-mediated miniature excitatory postsynaptic currents (mEPSCs). (1S,3R)-1-amino-cyclopentane-1,3-dicarboxylate (ACPD) or the group-I-selective agonist 3,5-dihydroxyphenylglycine evoked an inward current accompanied by a decrease in membrane conductance, consistent with the previously described closure of potassium channels by group I agonists. The increased cellular excitability was accompanied by an increase in mEPSC frequency in some cells. When calcium entry was blocked by cadmium, ACPD or the group-II-selective agonist 2-(2,3-dicarboxycyclopropyl)-glycine reduced the mEPSC frequency. L-2-amino-4-phosphonobutyric acid (L-AP4), a group-III-selective agonist, caused a similar decrease. The concentration-dependence of L-AP4-mediated inhibition was most consistent with activation of mGluR8. We investigated two possible effector mechanisms for the group III presynaptic receptor. Bath application of forskolin or 3-isobutyl-1-methylxantine had no effect on mEPSC frequency. Increasing calcium influx by raising extracellular K+ caused a large increase in the mEPSC frequency but did not enhance L-AP4-mediated inhibition. Thus inhibition of mEPSCs involves a mechanism downstream of calcium entry and appears to be independent of adenosine 3',5'-cyclic monophosphate. Our results indicate that both group II and III receptors can inhibit glutamate release at mitral cell terminals. Although group II/III receptors had a similar effect on mEPSCs, differences in location on nerve terminals and in glutamate sensitivity suggest that each mGluR may have discrete actions on mitral cell activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-3077
pubmed:author
pubmed:issnType
Print
pubmed:volume
78
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1468-75
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:9310436-Adenylate Cyclase, pubmed-meshheading:9310436-Animals, pubmed-meshheading:9310436-Animals, Newborn, pubmed-meshheading:9310436-Axons, pubmed-meshheading:9310436-Cadmium, pubmed-meshheading:9310436-Calcium Channels, pubmed-meshheading:9310436-Cells, Cultured, pubmed-meshheading:9310436-Cycloleucine, pubmed-meshheading:9310436-Electric Stimulation, pubmed-meshheading:9310436-Excitatory Amino Acid Agonists, pubmed-meshheading:9310436-Membrane Potentials, pubmed-meshheading:9310436-Neurons, pubmed-meshheading:9310436-Neuroprotective Agents, pubmed-meshheading:9310436-Olfactory Bulb, pubmed-meshheading:9310436-Patch-Clamp Techniques, pubmed-meshheading:9310436-Rats, pubmed-meshheading:9310436-Receptors, Metabotropic Glutamate, pubmed-meshheading:9310436-Synaptic Transmission, pubmed-meshheading:9310436-Tetrodotoxin, pubmed-meshheading:9310436-alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
pubmed:year
1997
pubmed:articleTitle
Modulation of mEPSCs in olfactory bulb mitral cells by metabotropic glutamate receptors.
pubmed:affiliation
Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.