Key Points
- This study aims to understand how intracellular acidosis affects calcium levels and relaxation in cardiac myocytes from guinea pigs.
- Isolated guinea pig cardiac myocytes subjected to acidosis using NH4Cl prepulses.
- Fluorescence measured with indo 1 to assess changes in intracellular Ca2+ levels.
- Voltage-clamped cells examined for transient inward current under control and acidosis conditions.
- Acidosis decreased contraction and prolonged fluorescence transient, indicating altered calcium handling.
- In acidosis, the rate of decline in calcium fluorescence was significantly slower; time to 50% recovery increased by 57%.
- Amiloride or ethylisopropylamiloride presence eliminated differences in current between control and acidosis.
Structured PICO
PPopulationIsolated cardiac myocytes from the guinea pig
IInterventionIntracellular acidosis (imposed by NH4Cl prepulses)
CComparatorControl conditions
OOutcomeRelaxation and decline in intracellular Ca2+ (measured using indo 1 fluorescence) and transient inward currentsurrogate
Intracellular acidosis slows Ca2+ efflux via Na+/Ca2+ exchange in guinea pig cardiac myocytes due to increased intracellular Na+ from enhanced Na+/H+ exchange activity.