Nitric oxide synthase expression in the cerebral cortex of patients with epilepsy.
OBJECTIVE
Nitric oxide (NO), a short-lived radical synthesized from L-arginine by activation of the enzyme nitric oxide synthase (NOS), has been implicated in the pathophysiology of epilepsy by some investigators. However, the current data about NO and NOS in epilepsy are controversial and are derived only from animal models of epilepsy. In this study we investigated possible changes in NOS expression in the cerebral cortex of patients with epilepsy.


METHODS
Qualitative and quantitative parameters of the immunolabeling pattern of the neuronal, endothelial, and inducible isoforms of NOS were analyzed in biopsy material obtained from patients with short and long seizure history and from patients without epilepsy.


RESULTS
The comparative study showed that in the cerebral cortex of patients with epilepsy, particularly in those with a long seizure history, the number and labeling intensity of NOS-positive neurons increased, and that a subpopulation of nonpyramidal GABAergic neurons (type II NOS neurons) was responsible for this phenomenon.


CONCLUSIONS
The fact that NOS upregulation is more evident in patients with a long seizure history suggests that this is a consequence of seizures, acting probably as an adaptative response to the sustained release of excitatory amino acids.
González-Hernández
T
T
Department of Anatomy, Pathology and Histology, Faculty of Medicine, University of La Laguna, Tenerife, Spain. tgonhern@ull.es
García-Marín
V
V
Pérez-Delgado
M M
MM
González-González
M L
ML
Rancel-Torres
N
N
González-Feria
L
L
D000293:Adolescent; D000328:Adult; D001706:Biopsy; D002540:Cerebral Cortex / Q000737:chemistry / Q000201:enzymology*; D002648:Child; D004727:Endothelium / Q000201:enzymology; D004827:Epilepsy / Q000201:enzymology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000378:metabolism*; D020033:Protein Isoforms
D020033:Protein Isoforms; D019001:Nitric Oxide Synthase