Linked Life Data

14622176

Source:http://linkedlifedata.com/resource/pubmed/id/14622176

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2003-11-18
pubmed:abstractText
The main inhibitory neurotransmitter in the mammalian forebrain is gamma-amino butyric acid (GABA), which acts through A and B type receptors. GABAA receptors mediate inhibition via an increase in membrane conductance (shunting) and/or membrane potential hyperpolarization. Shunting inhibition is thought to decrease the gain between neural input and output, and thus to act as a divisor, but may do so only below the spike threshold. To investigate the role of shunting inhibition in neocortical neurons, whole-cell patch-clamp recordings were obtained from layer V pyramidal cells of somatosensory cortex in juvenile rats. Sub- and suprathreshold voltage responses were elicited by somatic step current injections and a shunting conductance was generated via a dynamic clamp. Increasing the dynamic clamp shunting conductance led to a parallel shift of the current-discharge curves and a reduced slope of the current-voltage relationship, i.e. a decrease of neural gain. Selective activation of GABAAA receptors with the competitive agonist isoguvacine or rises of endogenous GABA with the specific reuptake blocker nipecotic acid led to a proportional decrease of subthreshold membrane voltage, but a constant offset of discharge rates, thus acting like a shunting conductance. Similarly, isoguvacine and nipecotic acid decreased the gain of excitatory postsynaptic potentials. In all three experimental conditions, shunting inhibition divisively affected subthreshold voltages, while the time-averaged suprathreshold membrane potential was offset by a constant amount. I conclude that shunting inhibition in pyramidal cells has a dual impact on neural output: it is divisive for subthreshold voltages but subtractive for spike frequencies.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0953-816X
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2159-65
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:14622176-Animals, pubmed-meshheading:14622176-Animals, Newborn, pubmed-meshheading:14622176-Differential Threshold, pubmed-meshheading:14622176-Dose-Response Relationship, Drug, pubmed-meshheading:14622176-Drug Interactions, pubmed-meshheading:14622176-Electric Conductivity, pubmed-meshheading:14622176-Excitatory Amino Acid Agonists, pubmed-meshheading:14622176-GABA Agonists, pubmed-meshheading:14622176-GABA Antagonists, pubmed-meshheading:14622176-Isonicotinic Acids, pubmed-meshheading:14622176-Membrane Potentials, pubmed-meshheading:14622176-Neocortex, pubmed-meshheading:14622176-Neural Inhibition, pubmed-meshheading:14622176-Nipecotic Acids, pubmed-meshheading:14622176-Patch-Clamp Techniques, pubmed-meshheading:14622176-Picrotoxin, pubmed-meshheading:14622176-Pyramidal Cells, pubmed-meshheading:14622176-Rats, pubmed-meshheading:14622176-Rats, Wistar, pubmed-meshheading:14622176-Receptors, GABA-A, pubmed-meshheading:14622176-Somatosensory Cortex, pubmed-meshheading:14622176-Time Factors, pubmed-meshheading:14622176-alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
pubmed:year
2003
pubmed:articleTitle
Differential arithmetic of shunting inhibition for voltage and spike rate in neocortical pyramidal cells.
pubmed:affiliation
Institute of Physiology, University of Bern, Bühlplatz 5, CH-3012 Bern, Switzerland. ulrich@pyl.unibe.ch
pubmed:publicationType
Journal Article, Comparative Study, In Vitro, Research Support, Non-U.S. Gov't