The effect of menadione on sarcoplasmic reticulum Ca2+ and contractions of single guinea-pig cardiomyocytes.
J Physiol Pharmacol
; 42(2): 221-34, 1991 Jun.
Article
em En
| MEDLINE
| ID: mdl-1782417
ABSTRACT
We investigated the effect of 2-methyl-1,4-naphtoquinone (Menadione) on sarcoplasmic reticulum (SR) Ca2+ content and electrically stimulated contractions (ESCs) of single isolated myocytes of guinea-pig ventricular myocardium. The contractures initiated by means of microinjections of caffeine into the close vicinity of the cell were used as an indirect index of the SR Ca2+ content. Superfusion of the cells for 45 min with Menadione resulted in gradual disappearance of contractile responses to caffeine, prolongation of time to peak amplitude of ESCs by 48 +/- 15% and complete inhibition of postrest and postextrasystolic potentiation. These results are consistent with those of Floreani and Carpenedo (7) who found that Menadione strongly inhibits the SR Ca2+ ATPase. Despite depletion of the SR Ca2+ the amplitude of ESCs did not change which suggests that contractions were initiated in the cells treated with Menadione by Ca2+ derived from the sources other than the SR.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Retículo Sarcoplasmático
/
Vitamina K
/
Cálcio
/
Contração Miocárdica
/
Miocárdio
Limite:
Animals
Idioma:
En
Revista:
J Physiol Pharmacol
Assunto da revista:
FARMACOLOGIA
/
FISIOLOGIA
Ano de publicação:
1991
Tipo de documento:
Article
País de afiliação:
Polônia