Effects of mercury on the contractility of isolated rat cardiac muscle
Braz. j. med. biol. res
; 25(10): 1037-40, 1992. graf
Article
em En
| LILACS
| ID: lil-134649
Biblioteca responsável:
BR26.1
RESUMO
The effects of increasing concentrations of mercury (Hg2+) chloride (1, 2.5, 5 and 10 microM) were studied on isometrically contracting papillary muscles from female rats (Wistar, EPM strain) weighing 150 to 180 g. Hg2+ promoted an increase of 12.7 +/- 2.2% in the developed force at 1 microM. At 2.5 microM, force values were similar to control, decreasing progressively as Hg2+ concentration increased to 5 (-13 +/- 6.4%) and 10 microM (-37 +/- 12.3%). Potentiated post-rest contractions (PRC) were also determined after 15-, 30- and 60-s pauses. There was a progressive reduction of the potentiated PRCs relative to their respective steady-state control contractions with increasing concentrations of HgCl2. Since in several tissues including myocardium Hg2+ inhibits the activity of Ca2+ and Na(+)-K(+)-ATPases the results described here suggest that Hg2+, at lower concentrations, could increase force by inhibiting Na(+)-K(+)-ATPase, while at higher concentrations Hg2+ would decrease relative PRC potentiation by inhibiting sarcoplasmic reticulum Ca(2+)-ATPase
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Base de dados:
LILACS
Assunto principal:
Técnicas In Vitro
/
Cloreto de Mercúrio
/
Contração Miocárdica
Idioma:
En
Ano de publicação:
1992
Tipo de documento:
Article
/
Congress and conference