[Seizure-linked hippocampal plasticity and protection against excitotoxicity: possible role of neuropeptide-y].
OBJECTIVE
Changes occurring in neuropeptide-Y immunoreactivity after kainic acid injection in rats and their possible consequences on seizure-brain damage were studied.


METHODS
First, an intra-hippocampal kainic acid injection was performed (n = 7), inducing an ectopic and bilateral neuropeptide-Y immunoreactivity in mossy fibers. On the side of the injection, this neuropeptide-Y staining was associated with dramatic neuronal loss whereas, in the contralateral hippocampus staining was observed without associated neuronal loss. The CA3 a-b pyramidal cell loss induced by an intra-ventricular kainic acid injection was then compared between a control group (n = 6) and a pre-conditioned group (n = 6) characterized by neuropeptide-Y staining in the mossy fibers obtained by a previous contralateral intra-hippocampal kainic acid injection as described.


RESULTS
In the pre-conditioned group, the CA3 a-b pyramidal cell loss was significantly lower (m = 33.5%) than in the control group (m = 86.6%). The neuropeptide-Y inhibiting the pre-synaptic release of glutamate, glutamate-related epileptic-brain damage could be reduced when neuropeptide-Y is expressed by granulated cells.


CONCLUSIONS
Seizure-linked plasticity could induce a self-protection phenomenon against excitotoxic lesions possibly partially mediated by de novo neuropeptide-Y mossy fiber expression.
Laboratoire de neurobiologie et Neuro-Imagerie Expérimentales, Université Bordeaux 2.
B
B
el Bahh
D
D
Lurton
M
M
Coussemacq
L
L
Sundstrom
A
A
Rougier
D000818:Animals; D002452:Cell Count / Q000187:drug effects; D004827:Epilepsy / Q000139:chemically induced* / Q000517:prevention & control*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D007608:Kainic Acid; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects / Q000378:metabolism; D009473:Neuronal Plasticity / Q000187:drug effects; D009478:Neuropeptide Y / Q000378:metabolism* / Q000502:physiology; D017966:Pyramidal Cells / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D009478:Neuropeptide Y; D007608:Kainic Acid
Plasticité hippocampique induite par les crises épileptiques et protection endogène contre l'excitotoxicité. Possible implication du neuropeptide-Y.