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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
26
|
| pubmed:dateCreated |
1988-10-19
|
| pubmed:abstractText |
Treatment of bovine chromaffin cells with 40 mM KCl stimulates a 3-fold increase in total methionine enkephalin immunoreactivity (medium plus cells) and a 4-fold increase in proenkephalin mRNA (mRNAenk). These effects of KCl, which are dependent on extracellular calcium, can be blocked by treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA), although release of methionine enkephalin appears less affected. Using fura-2-loaded chromaffin cells and a dual-excitation wavelength spectrofluorometer, we have examined whether the actions of KCl and TPA on methionine enkephalin synthesis and release can be explained by changes in intracellular free calcium ([Ca2+]i). KCl produced a rapid 600 nM increase in [Ca2+]i from resting levels of approximately 170 nM. Subsequently, [Ca2+]i declined to a new steady-state plateau which was approximately 275 nM higher than the original resting levels. The postdepolarization plateau of [Ca2+]i was reduced by TPA, (-)-(R)-202,791 (a dihydropyridine calcium channel antagonist), and LaCl3 (a nonselective calcium channel blocker). TPA also inhibited potentiation of the KCl-stimulated plateau of [Ca2+]i due to (+)-(S)-202,791, a calcium channel agonist. In contrast, TPA had no effect on resting [Ca2+]i and only slightly inhibited the initial rapid KCl-stimulated increase in [Ca2+]i. The inhibitory effects were maintained for 24 h in the continuous presence of TPA. We conclude 1) that TPA inhibits enkephalin synthesis by inactivating dihydropyridine-sensitive voltage-dependent calcium channels, 2) that these channels alone maintain elevated [Ca2+]i following KCl depolarization, and 3) that sustained elevation in [Ca2+]i is necessary in order to increase enkephalin synthesis in KCl-treated chromaffin cells.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Enkephalin, Methionine,
http://linkedlifedata.com/resource/pubmed/chemical/Enkephalins,
http://linkedlifedata.com/resource/pubmed/chemical/Ion Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Lanthanum,
http://linkedlifedata.com/resource/pubmed/chemical/Nicotinic Acids,
http://linkedlifedata.com/resource/pubmed/chemical/Oxadiazoles,
http://linkedlifedata.com/resource/pubmed/chemical/PN 202-791,
http://linkedlifedata.com/resource/pubmed/chemical/Potassium Chloride,
http://linkedlifedata.com/resource/pubmed/chemical/RNA, Messenger,
http://linkedlifedata.com/resource/pubmed/chemical/Tetradecanoylphorbol Acetate,
http://linkedlifedata.com/resource/pubmed/chemical/lanthanum chloride
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Sep
|
| pubmed:issn |
0021-9258
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
15
|
| pubmed:volume |
263
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
13173-8
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| pubmed:dateRevised |
2003-11-14
|
| pubmed:meshHeading |
pubmed-meshheading:2458344-Animals,
pubmed-meshheading:2458344-Calcium,
pubmed-meshheading:2458344-Cattle,
pubmed-meshheading:2458344-Enkephalin, Methionine,
pubmed-meshheading:2458344-Enkephalins,
pubmed-meshheading:2458344-Ion Channels,
pubmed-meshheading:2458344-Lanthanum,
pubmed-meshheading:2458344-Nicotinic Acids,
pubmed-meshheading:2458344-Oxadiazoles,
pubmed-meshheading:2458344-Potassium Chloride,
pubmed-meshheading:2458344-RNA, Messenger,
pubmed-meshheading:2458344-Tetradecanoylphorbol Acetate
|
| pubmed:year |
1988
|
| pubmed:articleTitle |
Voltage-regulated calcium channels involved in the regulation of enkephalin synthesis are blocked by phorbol ester treatment.
|
| pubmed:affiliation |
Merrell Dow Research Institute, Cincinnati, Ohio 45215.
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| pubmed:publicationType |
Journal Article
|