Linked Life Data

14999048

Source:http://linkedlifedata.com/resource/pubmed/id/14999048

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-6-23
pubmed:abstractText
Selective activation of neuronal functions by Ca(2+) is determined by the kinetic profile of the intracellular calcium ([Ca(2+)](i)) signal in addition to its amplitude. Concurrent electrophysiology and ratiometric calcium imaging were used to measure transmembrane Ca(2+) current and the resulting rise and decay of [Ca(2+)](i) in differentiated pheochromocytoma (PC12) cells. We show that equal amounts of Ca(2+) entering through N-type and L-type voltage-gated Ca(2+) channels result in significantly different [Ca(2+)](i) temporal profiles. When the contribution of N-type channels was reduced by omega-conotoxin MVIIA treatment, a faster [Ca(2+)](i) decay was observed. Conversely, when the contribution of L-type channels was reduced by nifedipine treatment, [Ca(2+)](i) decay was slower. Potentiating L-type current with BayK8644, or inactivating N-type channels by shifting the holding potential to -40 mV, both resulted in a more rapid decay of [Ca(2+)](i). Channel-specific differences in [Ca(2+)](i) decay rates were abolished by depleting intracellular Ca(2+) stores with thapsigargin or by blocking ryanodine receptors with ryanodine, suggesting the involvement of Ca(2+)-induced Ca(2+) release (CICR). Further support for involvement of CICR is provided by the demonstration that caffeine slowed [Ca(2+)](i) decay while ryanodine at high concentrations increased the rate of [Ca(2+)](i) decay. We conclude that Ca(2+) entering through N-type channels is amplified by ryanodine receptor mediated CICR. Channel-specific activation of CICR provides a mechanism whereby the kinetics of intracellular Ca(2+) leaves a fingerprint of the route of entry, potentially encoding the selective activation of a subset of Ca(2+)-sensitive processes within the neuron.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0022-3077
pubmed:author
pubmed:issnType
Print
pubmed:volume
92
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
135-43
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Distinct intracellular calcium profiles following influx through N- versus L-type calcium channels: role of Ca2+-induced Ca2+ release.
pubmed:affiliation
Program of Neuroscience, Department of Neuobiology, University of Massachusetts Medical School, Worcester 01605, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.