Linked Life Data

7841125

Source:http://linkedlifedata.com/resource/pubmed/id/7841125

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1995-3-6
pubmed:abstractText
Rod on-bipolar cell light responses are mediated by a class of metabotropic glutamate receptor which is coupled via a G-protein to the control of a cGMP cascade, with cGMP acting to open cation channels, whilst off-bipolar cells possess ionotropic glutamate receptors. Whole-cell voltage-clamp recordings were obtained from on- and off-bipolar cells of dark-adapted dogfish retinal slices, identified by their light responses. Isolated cells were exposed to concentration-jumps of glutamate. At negative voltage-clamp potentials, on-bipolar cells responded to glutamate with outward currents with a mean delay of 10.8 ms, whilst off-bipolar cells responded with inward currents without any delay. Neither cell type showed desensitization to applied steps of glutamate. The dose-response relation for on-bipolar cells showed no gradual saturation, but increased linearly with a sharp cutoff above 200 microM glutamate. This dose-response relation could be fitted with a theoretical expression assuming Michaelis-Menten kinetics for the action of glutamate on receptors and a linear relation between the concentration of receptors bound to glutamate and the fall in cGMP this induces. The dose-response relation of off-bipolar cells showed saturation with a limiting slope of 2 at low glutamate concentrations, suggesting that two molecules of glutamate are required to open each channel by a cooperative mechanism. The glutamate receptor coupled cGMP cascade of rod on-bipolar cells can account for high synaptic voltage gain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0952-5238
pubmed:author
pubmed:issnType
Print
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1175-83
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:articleTitle
Responses of rod bipolar cells isolated from dogfish retinal slices to concentration-jumps of glutamate.
pubmed:affiliation
Department of Physiology, University College, London, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't