Reference - Detail
|Author||Yan HD, Ishihara K, Hanaya R, Kurisu K, Serikawa T, Sasa M.|
|Title||Voltage-dependent calcium channel abnormalities in hippocampal CA3 neurons of spontaneously epileptic rats.|
PURPOSE:Hippocampal CA3 neurons of spontaneously epileptic rats (SER; zi/zi, tm/tm), which show both absence-like seizures and tonic convulsions, exhibit a long-lasting depolarization shift with repetitive firing with a single stimulation of mossy fibers. Therefore a whole-cell patch-clamp study using temporarily dissociated hippocampal CA3 neurons from SER was performed to elucidate whether such abnormal excitability was due to abnormalities in voltage-dependent Ca(2+) channels (VDCCs).
METHODS:Hippocampal CA3 neurons were temporarily dissociated with enzymatic and mechanical treatments. In a voltage-clamp mode with whole-cell recording, depolarizing step pulses were applied to induce Ca(2+) currents in the presence of tetrodotoxin and tetraethylammonium.
RESULTS:The threshold level of the Ca(2+) current induced by depolarizing pulses was found to be lower in hippocampal CA3 neurons of SER compared with those of control Wistar rats. In addition, the Ca(2+) current peak amplitude was greater, and decay of the current was weaker in CA3 neurons of SER than in those of normal Wistar rats.
CONCLUSIONS:These findings suggest that enhancements of Ca(2+) influx into hippocampal CA3 neurons due to the easier activation properties of VDCCs, as well as a decrease in decay, are involved in SER epileptic seizures.
|MeSH||Action Potentials / physiology* Animals Calcium / pharmacology* Calcium Channels / physiology Epilepsy / genetics* Epilepsy / physiopathology Fluoresceins Hippocampus / cytology Hippocampus / physiopathology* Membrane Potentials / physiology Mossy Fibers, Hippocampal / physiology Neurons / drug effects Neurons / physiology* Organic Chemicals Patch-Clamp Techniques Rats Rats, Mutant Strains Rats, Wistar Tetraethylammonium Tetrodotoxin|
|WOS Category||CLINICAL NEUROLOGY|