Blockade of magnesium sulfate on transient outward K+ current and delayed rectifier K+ current in acutely isolated rat hippocampal neurons.
- Author:
Nan SANG
1
;
Zi-qiang MENG
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Cell Separation; Delayed Rectifier Potassium Channels; Female; Hippocampus; cytology; Magnesium Sulfate; pharmacology; Male; Neurons; drug effects; physiology; Neuroprotective Agents; pharmacology; Patch-Clamp Techniques; Potassium Channels; drug effects; metabolism; Potassium Channels, Voltage-Gated; Rats; Rats, Wistar
- From: Acta Pharmaceutica Sinica 2002;37(7):510-515
- CountryChina
- Language:Chinese
-
Abstract:
AIMTo study the effect of magnesium sulfate on transient outward K+ current (IA) and delayed rectifier K+ current (IK) in freshly dissociated hippocampal neurons of rats.
METHODSThe whole-cell patch clamp techniques were used.
RESULTSMagnesium sulfate reversibly reduced the amplitudes of IA and IK in a concentration-dependent and voltage-dependent, but not frequency-dependent manner. Half-blocking concentration (IC50) on IA and IK were 6.30 mmol.L-1 and 7.60 mmol.L-1, respectively. Magnesium sulfate (6 mmol.L-1) affected the activation process of IA and IK. Before and after application of the drug, the half-activation voltages of IA were (7 +/- 6) mV and (-7 +/- 11) mV (n = 10, P < 0.01), and the half-activation voltages of IK were (20 +/- 6) mV and (28 +/- 4) mV (n = 10, P < 0.01), but the slope factors were not changed. In addition, magnesium sulfate (6 mmol.L-1) also affected the inactivation process of IA. Before and after application of the drug, the half-inactivation voltages of IA were (-65 +/- 5) mV and (-89 +/- 6) mV (n = 10, P < 0.01).
CONCLUSIONMagnesium sulfate inhibited IA and IK in freshly dissociated hippocampal neurons of rats, which might contribute to protect the central neuronal system (CNS) against damages induced by ischemia and oxygen deprivation.
