Linked Life Data

8457855

Source:http://linkedlifedata.com/resource/pubmed/id/8457855

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1993-4-26
pubmed:abstractText
Paired-pulse facilitation was studied at the perforant path-granule cell synapses in the dentate gyrus of urethane-anesthetized rats. Extracellular field potentials comprising excitatory postsynaptic potentials (EPSPs) and population spikes (PSs) were used to compare facilitation of both responses at interpulse intervals between 10 and 1000 ms. In this model system EPSPs, produced at stimulus intensities well below the PS threshold, exhibited paired-pulse facilitation (PPF) at intervals less than 40 ms. Between 40 and 100 ms both responses were of equal size and from 200 to 1000 ms the second response exhibited paired-pulse depression (PPD). With higher stimulus intensities, PSs exhibited early (10-30 ms) and late (400-1000 ms) PPD and intermediate interval (40-200 ms) PPF. The enhanced PS amplitude during facilitation was accompanied by a modest decrease in EPSP slope and increase in PS latencies to onset and to peak. If PS amplitude was increased to the same extent by simply increasing stimulus intensity, an increase in EPSP slope and decrease in PS latencies to onset and peak were observed. Current source-density analysis revealed that the current sink generated by synaptic activation of granule cell dendrites was indistinguishable between control and facilitated responses up to the onset of the PS. However, the facilitated response exhibited a marked increase in the duration and amplitude of current flowing into the dendrites during the late phase of the EPSP. PPF of the PS was attenuated or blocked by the administration of the known NMDA receptor-ion channel blockers, MK-801, dextromethorphan and ketamine. The depressant effects of these pharmacological agents on facilitation shared the same time course as facilitation itself, peaking at 60 ms and lasting approximately 200 ms. These data suggest that facilitation in this situation is due to postsynaptic rather than presynaptic modulations, and is based upon an increase in the NMDA-mediated component of the evoked response. No increase in transmitter release, per se, could be demonstrated.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
604
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
273-82
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
NMDA receptors have a dominant role in population spike-paired pulse facilitation in the dentate gyrus of urethane-anesthetized rats.
pubmed:affiliation
Department of Veterinary Pharmacology and Toxicology, School of Veterinary Medicine, University of California, Davis 95616.
pubmed:publicationType
Journal Article