| L-type and Ca2+ release channel-dependent hierarchical Ca2+ signalling in rat portal vein myocytes. | |
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MedLine Citation:
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PMID: 9448946 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Ca2+ signalling events and whole-cell Ca2+ currents were analyzed in single myocytes from rat portal vein by using a laser scanning confocal microscope combined with the patch-clamp technique. In myocytes in which the intracellular Ca2+ store was depleted or Ca2+ release channels were blocked by 10 microM ryanodine, inward Ca2+ currents induced slow and sustained elevations of [Ca2+]i. These Ca2+ responses were suppressed by 1 microM oxodipine and by depolarizations to +120 mV, a potential close to the reversal potential for Ca2+ ions, suggesting that they reflected Ca2+ influx through L-type Ca2+ channels. With functioning intracellular Ca2+ stores, flash photolysis of caged Ca2+ gave rise to a small increase in [Ca2+]i with superimposed Ca2+ sparks, reflecting the opening of clustered Ca2+ release channels. Brief Ca2+ currents in the voltage range from -30 to +10 mV triggered Ca2+ sparks or macrosparks that did not propagate in the entire line-scan image. Increasing the duration of Ca2+ current for 100 ms or more allowed the trigger of propagating Ca2+ waves which originated from the same initiation sites as the caffeine-activated response. Both Ca2+ sparks and initiation sites of Ca2+ waves activated by Ca2+ currents were observed in the vicinity of areas that excluded the Ca2+ probes, reflecting infoldings of the plasma membrane close to the sarcoplasmic reticulum, as revealed by fluorescent markers. The hierarchy of Ca2+ signalling events, from submicroscopic fundamental events to elementary events (sparks) and propagated waves, provides an integrated mechanism to regulate vascular tone. |
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Authors:
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S Arnaudeau; F X Boittin; N Macrez; J L Lavie; C Mironneau; J Mironneau |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Cell calcium Volume: 22 ISSN: 0143-4160 ISO Abbreviation: Cell Calcium Publication Date: 1997 Nov |
Date Detail:
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Created Date: 1998-03-24 Completed Date: 1998-03-24 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8006226 Medline TA: Cell Calcium Country: SCOTLAND |
Other Details:
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Languages: eng Pagination: 399-411 Citation Subset: IM |
Affiliation:
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Laboratoire de Physiologie Cellulaire et Pharmacologie Moléculaire, CNRS ESA 5017, Université de Bordeaux II, France. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Calcium / metabolism* Calcium Channels / metabolism* Electrophysiology Intracellular Membranes / metabolism Portal Vein / cytology, metabolism, physiology Rats Rats, Wistar Sarcoplasmic Reticulum / metabolism*, physiology Signal Transduction* |
| Chemical | |
Reg. No./Substance:
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0/Calcium Channels; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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