Depression of hippocampal low calcium field bursts by the antiepileptic drug valproic acid.
The antiepileptic drug valproic acid (VPA) reduces the occurrence of the rhythmic and synchronous bursts produced by hippocampal neurons maintained 'in vitro' and bathed in Ringer-containing low-Ca2+ (0.2 mM), high-Mg2+ (4.0 mM). In this medium, synaptic transmission is blocked, thus demonstrating an action of VPA unrelated to potentiation of GABAergic phenomena. This conclusion is reenforced by the persistence of VPA effects in the presence of bicuculline. Also, the VPA doses effective in reducing the low-calcium synchronous burst in the hippocampal slice are similar to the free plasma levels of VPA observed to exert anticonvulsant effects in kindled rats.
Agopyan
N
N
Avoli
M
M
Rieb
L
L
Tancredi
V
V
D000818:Animals; D002118:Calcium / Q000502:physiology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects; D014635:Valproic Acid / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D007473:Ion Channels; D005680:gamma-Aminobutyric Acid; D014635:Valproic Acid; D002118:Calcium