Inhibition of sodium currents in acutely isolated hippocampal CA1 neurons of rats by magnesium sulfate.
- Author:
Nan SANG
1
;
Zi-Qiang MENG
Author Information
1. Institute of Environmental Medicine and Toxicology, Shanxi University, Taiyuan 030006.
- Publication Type:Journal Article
- MeSH:
Animals;
Hippocampus;
cytology;
drug effects;
physiology;
Magnesium Sulfate;
pharmacology;
Neurons;
drug effects;
physiology;
Patch-Clamp Techniques;
Rats;
Rats, Wistar;
Sodium Channel Blockers;
pharmacology;
Sodium Channels;
physiology
- From:
Acta Physiologica Sinica
2002;54(6):539-543
- CountryChina
- Language:Chinese
-
Abstract:
The effects of magnesium sulfate (MgSO4) on sodium currents (Na(+) currents) were studied in freshly dissociated hippocampal CA(1) neurons of rat using the whole-cell patch-clamp technique. The results indicated that MgSO4 caused a concentration-dependent and voltage-dependent decrease in Na(+) currents. The half-inhibitory concentration (IC(50)) was 4.05 mmol/L. This action was frequency-independent. The results also showed that 4 mmol/L MgSO4 shifted the steady state activation curve of Na(+) currents towards positive potential (control V(h)=-55.8+/-6.8 mV, MgSO4 V(h)=-34.2+/-6.2 mV, n=8, P<0.01) without changing the slope factor. However, the steady state inactivation curve was not affected. These results suggest that blockade of Na(+) currents by MgSO4 might be an interpretation for its neuroprotection against damages induced by ischemia and oxygen deprivation.
