SUBACUTE ELECTRICAL STIMULATION IN HIPPOCAMPUS OF PATIENTS WITH TEMPORAL LOBE EPILEPSY ENHANCES THE TISSUE LEVELS OF INHIBITORY AND EXCITATORY AMINOACIDS
Abstract number :
3.060
Submission category :
Year :
2002
Submission ID :
3391
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Manola Cuellar-Herrera, Marcos Velasco-Campos, Francisco Velasco-Campos, Ana Luisa Velasco-Monroy, Leticia Neri-Bazan, Luisa Rocha. Farmacobiologia, Centro de Investigacion y Estudios Avanzados del IPN, Mexico, D.F., Mexico, D.F., Mexico; Coordinacion de
RATIONALE: Patients with temporal lobe epilepsy (TLE) present decreased GABA content in the epileptic area (hippocampus). In contrast, subacute electrical stimulation of the hippocampus (SAHCS) in patients with TLE induces inhibitory effects. We suggest that the SAHCS in patients with TLE increases the content of inhibitory aminoacids.
METHODS: The tissue content of inhibitory and excitatory aminoacids was determined by HPLC technique, in hippocampus and parahippocampus surgically resected from patients with TLE pharmacologically resistant and submitted to SAHCS (SAHCS group) (n=4). SAHCS consisted on continuous stimulation with biphasic pulses (130/sec in frequency, 0.45 sec in duration with an amplitude of 0.2-0.4 mA and delivered by a Medtronic DBS pulse generator. Control tissue was obtained from subjects died by accident without neurological damage (C group, n=3) and patients with TLE without electrical stimulation (E group, n=10).
RESULTS: When compared with the E group, the SAHCS group showed hippocampal increased levels of GABA (332%), taurine (126%), glycine (114%), glutamine (220%) and glutamate (296%), whereas in parahippocampus there were high levels of taurine (156%), glutamine (181%) and aspartate (199%). In contrast with the C group, the E group did not show significant changes.
CONCLUSIONS: These results suggest that the SACHS activates inhibitory and excitatory neurotransmitters in hippocampus and parahippocampus of patients with TLE epilepsy. It is possible that the cerebral electrical stimulation with antiepileptic effects in the epileptic focus and its surrounding area, stimulates endogenous mechanisms that restrict or reduce the seizure activity.
[Supported by: CONACyT (grant 31702-M).]