Evaluation of GABA system and cell damage in parahippocampus of patients with temporal lobe epilepsy showing antiepileptic effects after subacute electrical stimulation.
OBJECTIVE
The gamma-aminobutyric acid (GABA) system and neuronal loss were evaluated in the parahippocampal cortex (PHC) of patients with intractable mesial temporal lobe epilepsy (MTLE) who received subacute electrical stimulation and showed antiepileptic effects.


METHODS
GABA tissue content, GABA(A) and benzodiazepine (BZD) receptor levels, as well as neuronal density were determined in PHC of five patients (ESAE group) with an MTLE history of 14.8 +/- 2.5 years and seizure frequency of 11 +/- 2.9 per month, two (40%) of them with mesial sclerosis. This group demonstrated antiepileptic effects after subacute electrical stimulation (130 Hz, 450 micros, 200-400 microA), applied continuously during 16 to 20 days in PHC. Values were compared with those obtained from patients with severe MTLE (history of 21.7 +/- 2.8 years and seizure frequency of 28.2 +/- 14 per month) in whom electrical stimulation did not induce antiepileptic effects (ESWAE group, n = 4), patients with MTLE in whom no electrical stimulation was applied (MTLE group, n = 4), and autopsy material acquired from subjects without epilepsy (n = 4 obtained from three subjects).


RESULTS
The ESAE group demonstrated high GABA tissue levels (219%), as well as a significantly higher cell count (58.5%) when compared with the MTLE group. The ESWAE group showed enhanced BZD-receptor levels (38%), whereas their values for GABA tissue levels and GABA(A) receptor were similar to those obtained from the MTLE group.


CONCLUSIONS
It is suggested that subacute electrical stimulation of PHC is more effective in patients with less severe epilepsy, an effect associated with a high GABA tissue content and a low rate of cell loss.
Cuéllar-Herrera
Manola
M
Department of Pharmacobiology, Center for Investigation and Advanced Studies from IPN Mexico, Mexico City, Mexico.
Velasco
Marcos
M
Velasco
Francisco
F
Velasco
Ana Luisa
AL
Jiménez
Fiacro
F
Orozco
Sandra
S
Briones
Magdalena
M
Rocha
Luisa
L
D000328:Adult; D002452:Cell Count; D004599:Electric Stimulation Therapy; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D020534:Parahippocampal Gyrus / Q000737:chemistry* / Q000473:pathology*; D011963:Receptors, GABA-A / Q000032:analysis / Q000378:metabolism; D012720:Severity of Illness Index; D005680:gamma-Aminobutyric Acid / Q000032:analysis* / Q000502:physiology
D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid