Activation of calcium-sensitive potassium channels in L6 skeletal myocytes by arginine vasopressin requires extracellular calcium.
Biochem Biophys Res Commun
; 217(3): 1163-8, 1995 Dec 26.
Article
in En
| MEDLINE
| ID: mdl-8554572
ABSTRACT
The effects of extracellular application of arginine vasopressin (AVP) upon membrane currents in L6 skeletal myocytes was investigated using the whole-cell configuration of the patch-clamp technique. At 0 mV AVP produced large amplitude, transient outward currents that reversed when the clamping potential was changed to -100 mV (negative to EK). The effects of alterations in the extracellular K+ concentration upon the current reversal potential suggested that the current elicited by AVP was carried mainly by K+ ions. Intracellular dialysis with 10 microM inositol 1,4,5-trisphosphate (InsP3) elicited similar currents but only in 6/14 cells. Inclusion of 5 mg ml-1 heparin in the intracellular solutions was ineffective at inhibiting the current responses to AVP. The AVP-induced current was totally abolished when the intracellular EGTA concentration was increased from 0.05 mM to 10 mM or Ca2+ was removed from the extracellular perfusing solution. These results suggest that AVP produces activation of a Ca(2+)-sensitive K+ conductance in L6 skeletal myocytes by a process dependent upon extracellular Ca2+ and not intracellular Ca2+ release.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Arginine Vasopressin
/
Potassium Channels
/
Calcium
/
Muscles
Type of study:
Diagnostic_studies
Limits:
Animals
Language:
En
Journal:
Biochem Biophys Res Commun
Year:
1995
Document type:
Article
Affiliation country: