Linked Life Data

3401762

Source:http://linkedlifedata.com/resource/pubmed/id/3401762

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1988-9-15
pubmed:abstractText
We have previously shown that the calcium channel antagonist omega-conotoxin M-VII-A blocks neurotransmitter release from isolated nerve terminals (synaptosomes) from the electric organ of the electric ray (Yeager et al., J. Neurosci., 7 (1987) 2390-2396). We now demonstrate that a related but more readily available peptide, omega-conotoxin G-VI-A (CgTx), also blocks the release of transmitter from these terminals and, in addition, inhibits depolarization-dependent uptake of Ca2+ into these terminals. The half-maximal inhibitory concentration (IC50 for block of depolarization-evoked release and for depolarization-dependent uptake of Ca2+ are approximately 3 and 2 microM, respectively. These results suggest the inhibitory effects of CgTx are due to the inhibition of Ca2+ entry into synaptosomes through voltage-sensitive calcium channels. Assays of radioiodinated CgTx binding to electric organ synaptosomal membranes and synaptosomes appear to show a single binding site with an apparent dissociation constant (Kd) of 3-5 microM and toxin receptor densities of 290 and 52 pmol/mg protein, respectively. These CgTx receptor densities are equivalent to 6% of the total synaptosomal membrane protein and 1% of the total synaptosomal protein (assuming a molecular weight of 200 kDa for the toxin receptor). If the observed CgTx receptor densities reflect the actual densities of voltage-sensitive calcium channels in electric organ synaptosomal membranes and synaptosomes, these preparations would be the richest source of these channels yet described.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
453
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
247-56
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
The calcium channel antagonist, omega-conotoxin, and electric organ nerve terminals: binding and inhibition of transmitter release and calcium influx.
pubmed:affiliation
Department of Biological Sciences, University of Southern California, Los Angeles 90089-0371.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't