Hippocampal mobility-related theta activity is not diminished by vigabatrin, a GABAmimetic antiepileptic drug, in normal rats.
Lesions causing loss of hippocampal theta activity have been shown to result in spatial memory deficits in rats. On the other hand, hippocampal theta activity is thought to be associated only with motor activity, and its role in learning/memory is not clear. Vigabatrin, an inhibitor of GABA-tranasminase, causes elevation of brain GABA levels. Previously, we have found that subchronic administration of vigabatrin did not impair spatial learning/memory in a water maze task. This experiment was carried out to further examine the hippocampal effects of vigabatrin by studying whether vigabatrin at antiepileptic doses affects mobility-related hippocampal EEG. Administration of vigabatrin (100 mg/kg or 500 mg/kg, IP) to nonepileptic rats caused no significant changes in mobility-related rhythmic theta activity, and the relative spectral power of theta frequency had a slight increasing tendency. These results suggest that the vigabatrin-induced enhanced GABAergic inhibition does not disturb normal mobility-related hippocampal theta activity.
Ylinen
A
A
Department of Neurology, University of Kuopio, Finland.
Koivisto
E
E
Valjakka
A
A
Sirviö
J
J
Freund
T F
TF
Riekkinen
P
P
D000614:Aminocaproates / Q000494:pharmacology*; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013826:Theta Rhythm / Q000187:drug effects*; D020888:Vigabatrin; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D000614:Aminocaproates; D000927:Anticonvulsants; D005680:gamma-Aminobutyric Acid; D020888:Vigabatrin