Linked Life Data

1327679

Source:http://linkedlifedata.com/resource/pubmed/id/1327679

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1992-11-19
pubmed:abstractText
Long-term potentiation (LTP) is an example of a persistent change in synaptic function in the mammalian brain, thought to be essential for learning and memory. At the synapse between hippocampal CA3 and CA1 neurons LTP is induced by a Ca2+ influx through glutamate receptors of the NMDA (N-methyl-D-aspartate) type (see Collingridge et al 1992, this volume). How does a rise in [Ca2+]i lead to enhancement of synaptic function? We have tested the popular hypothesis that Ca2+ acts via a Ca(2+)-dependent protein kinase. We found that long-lasting synaptic enhancement was prevented by prior intracellular injection of potent and selective inhibitory peptide blockers of either protein kinase C (PKC) or Ca2+/calmodulin-dependent protein kinase II (CaMKII), such as PKC(19-31) or CaMKII(273-302), but not by control peptides. Evidently, activity of both PKC and CaMKII is somehow necessary for the postsynaptic induction of LTP. To determine if these kinases are also involved in the expression of LTP, we impaled cells with microelectrodes containing protein kinase inhibitors after LTP had already been induced. Strikingly, established LTP was not suppressed by a combination of PKC and CaMKII blocking peptides, or by intracellular postsynaptic H-7. However, established LTP remained sensitive to bath application of H-7. Thus, the persistent signal may be a persistent kinase, but if so, the kinase cannot be accessed within the postsynaptic cell. Evidence for a presynaptic locus of expression comes from our studies of quantal synaptic transmission under whole-cell voltage clamp. We find changes in synaptic variability expected to result from enhanced presynaptic transmitter release, but little or no increase in quantal size. Furthermore, miniature synaptic currents in hippocampal cultures are increased in frequency but not amplitude as a result of a glutamate-driven postsynaptic induction. The combination of postsynaptic induction and presynaptic expression necessitates a retrograde signal from the postsynaptic cell to the presynaptic terminal.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0300-5208
pubmed:author
pubmed:issnType
Print
pubmed:volume
164
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
176-91; discussion 192-6
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Persistent signalling and changes in presynaptic function in long-term potentiation.
pubmed:affiliation
Department of Molecular and Cellular Physiology, Stanford University Medical Center, CA 94305-5425.
pubmed:publicationType
Journal Article