Kindling-induced epilepsy alters calcium currents in granule cells of rat hippocampal slices.
Single electrode voltage-clamp recordings were obtained from dentate gyrus granule cells (GCs) in hippocampal slices of control and commissurally kindled rats. Two types of calcium currents, a transient and a sustained current, were studied in control and kindled neurons. The threshold of the transient calcium current was lowered in kindled GCs. The sustained calcium current was absent in kindled neurons but it could be restored by the intracellular administration of the calcium chelator EGTA. Our findings are consistent with the hypothesis that the loss of an intraneuronal calcium binding protein (Calbindin-D28K; CaBP) reduces the intraneuronal calcium buffering capacity in kindled neurons and results in the enhanced calcium-dependent inactivation of sustained calcium currents.
Mody
I
I
Department of Neurology and Neurological Sciences M016, Stanford University School of Medicine, CA 94305.
Reynolds
J N
JN
Salter
M W
MW
Carlen
P L
PL
MacDonald
J F
JF
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D004533:Egtazic Acid / Q000494:pharmacology; D004827:Epilepsy / Q000503:physiopathology*; D006624:Hippocampus / Q000166:cytology / Q000502:physiology / Q000503:physiopathology*; D066298:In Vitro Techniques; D007696:Kindling, Neurologic; D008297:Male; D008564:Membrane Potentials; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D015220:Calcium Channels; D004533:Egtazic Acid; D002118:Calcium