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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1990-6-4
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pubmed:abstractText |
At frog neuromuscular junctions immersed in solutions containing 0.5 mM Mn2+, verapamil (40 microM) reduced the increase in miniature end-plate potential (MEPP) frequency produced by tetanic stimulation (50 Hz, 2 min) of the motor nerve to 5% of that in the absence of verapamil. In solutions containing 5 mM Mg2+, verapamil reduced the tetanic increase in MEPP frequency to 8% of that in the absence of verapamil. Verapamil added to solutions containing 0.15 mM Ca2+ decreased the tetanic rise in MEPP frequency to 6% of the control value. In low Ca2+ (nominally Ca2(+)-free) solutions, verapamil decreased the tetanic rise to 70% of the control value. The present results suggest that Mn2+ and Mg2+, as well as Ca2+, enter the nerve terminal through Ca2+ channels during nerve stimulation and promote transmitter release. In addition to its effect on the Ca2+ channel, verapamil at higher concentrations appears to have inhibitory effects on the acetylcholine-gated end-plate channel and on the Na+ channel as suggested by its depressive effects on the amplitudes of MEPPs, end-plate potentials and nerve terminal action potentials.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0006-8993
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
5
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pubmed:volume |
510
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
289-95
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:2158851-Action Potentials,
pubmed-meshheading:2158851-Animals,
pubmed-meshheading:2158851-Calcium Channels,
pubmed-meshheading:2158851-Magnesium,
pubmed-meshheading:2158851-Manganese,
pubmed-meshheading:2158851-Motor Neurons,
pubmed-meshheading:2158851-Rana temporaria,
pubmed-meshheading:2158851-Verapamil
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pubmed:year |
1990
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pubmed:articleTitle |
Mn and Mg influxes through Ca channels of motor nerve terminals are prevented by verapamil in frogs.
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pubmed:affiliation |
Department of Physiology, Kawasaki Medical School, Okayama, Japan.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
|