Linked Life Data

20357104

Source:http://linkedlifedata.com/resource/pubmed/id/20357104

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
2010-4-1
pubmed:abstractText
Synaptic transmission at CNS synapses is often mediated by joint actions of multiple Ca(2+) channel subtypes, most prominently, P/Q- and N-type. We have proposed that P/Q-type Ca(2+) channels saturate type-preferring slots at presynaptic terminals, which impose a ceiling on the synaptic efficacy of the channels. To test for analogous interactions for presynaptic N-type Ca(2+) channels, we overexpressed their pore-forming Ca(V)2.2 subunit in cultured mouse hippocampal neurons, recorded excitatory synaptic transmission from transfected cells, and dissected the contributions of N-, P/Q-, and R-type channels with subtype-specific blockers. Overexpression of Ca(V)2.2 did not increase the absolute size of the EPSC even though somatic N-type current was augmented by severalfold. Thus, the strength of neurotransmission is saturated with regard to levels of Ca(2+) channel expression for both N-type and P/Q-type channels. Overexpression of Ca(2+)-impermeable Ca(V)2.2 subunits decreased EPSC size, corroborating competition for channel slots. Striking asymmetries between N- and P/Q-type channels emerged when their relative contributions were compared with channel overexpression. Overexpressed N-type channels could competitively displace P/Q-type channels from P/Q-preferring slots and take over the role of supporting transmission. The converse was not found with overexpression of P/Q-type channels, regardless of their C-terminal domain. We interpret these findings in terms of two different kinds of presynaptic slots at excitatory synapses, one accepting N-type channels but rejecting P/Q-type (N(specific)) and the other preferring P/Q-type but also accepting N-type (PQ(preferring)). The interaction between channels and slots governs the respective contributions of multiple channel types to neurotransmission and, in turn, the ability of transmission to respond to various stimulus patterns and neuromodulators.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
31
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4536-46
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Different relationship of N- and P/Q-type Ca2+ channels to channel-interacting slots in controlling neurotransmission at cultured hippocampal synapses.
pubmed:affiliation
Department of Molecular and Cellular Physiology, Beckman Center, Stanford University School of Medicine, Stanford, California 94305-5345, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural