Published 4 issues per year
ISSN Print: 2155-014X
ISSN Online: 2155-0158
Action of Nitrogen Oxides and Hydrogen Peroxide on Ca2+ Transport in Sarcoplasmic Reticulum of Permeabilized Myocytes of Utera
ABSTRACT
Investigations were conducted on a model of digitonin-permeabilized myocytes from pig uterus using 45Ca2+. We have established that in the presence of 10 mM of sodium azide, which reliably represses the energy-dependent accumulation of Ca2+ in mitochondria, sodium nitroprusside (10 μM − 0.1 mM), nitrite-anion (0.1 μM − 10 μM) and hydrogen peroxide (0.1 μM − 10 μM) stimulated energy-dependent introduction of Ca2+ in sarcoplasmic reticulum. When studying processes of passive Ca2+ release from this pool, which was preliminary accumulated in the ATP-dependent process, we have discovered that administration of sodium nitroprusside (10 μM), nitrite-anion (10 nM − 0.1 mM) and hydrogen peroxide (10 nM) resulted in the decline of passive Ca2+ release, while 0.1 mM of H2O2 resulted in the opposite effect. These findings allow us to assume that the tested chemicals can reduce Ca2+ concentration in the myoplasm, and hence, the contractile activity, acting on the level of sarcoplasmic reticulum.