Document Detail


Effects of phosphorylation-related drugs on slow Ca2+ tail current in guinea-pig detrusor cells.
MedLine Citation:
PMID:  10323268     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In isolated guinea-pig detrusor cells, large conditioning depolarizations evoke slowly deactivating Ca2+ tail currents, considered to represent the second open state. The possible involvement of channel phosphorylation in this open state was examined. Application of isoprenaline caused a marginal increase in Ca2+ channel current evoked by simple depolarization, while forskolin did not. During application of either drug, slow-tail currents were never observed after simple depolarizations. The conditions necessary to induce slow-tail currents were not changed, even when cyclic AMP, ATP-gamma-S (adenosine 5'-O-(3-thiotriphosphate)), GDP-beta-S (guanosine 5'-O-(2-thiodiphosphate)) (in the pipette) or H-7 (1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride) (to the bathing solution) was applied. The frequent depolarization protocol, known to facilitate Ca2+ current via Ca2+ and cyclic AMP-dependent phosphorylation mechanism(s) in cardiac myocytes, did not induce slow-tail currents. These results suggest that the transition of Ca2+ channels to the second open state during large depolarization is not a result of (voltage-operated) channel phosphorylation itself. Possible underlying mechanisms are discussed.
Authors:
L M Smith; S Kajioka; A F Brading; S Nakayama
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of pharmacology     Volume:  370     ISSN:  0014-2999     ISO Abbreviation:  Eur. J. Pharmacol.     Publication Date:  1999 Apr 
Date Detail:
Created Date:  1999-07-16     Completed Date:  1999-07-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1254354     Medline TA:  Eur J Pharmacol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  187-93     Citation Subset:  IM    
Affiliation:
Department of Physiology, School of Medicine, Nagoya University, Japan.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Agonists / pharmacology
Animals
Calcium Channels / drug effects*,  physiology
Cyclic AMP / pharmacology
Electric Stimulation
Female
Guinea Pigs
Isoproterenol / pharmacology
Male
Membrane Potentials / drug effects
Muscle, Smooth / drug effects*,  physiology
Patch-Clamp Techniques
Phosphorylation
Urinary Bladder / drug effects
Chemical
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Calcium Channels; 60-92-4/Cyclic AMP; 7683-59-2/Isoproterenol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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