J Korean Pediatr Soc.  2001 Dec;44(12):1432-1440.

The Immunohistochemical Expression of Neuronal Nitric Oxide Synthase in Rat Hippocampus after Pentylenetetrazole-Induced Seizures

• Kim DK
• Jang TJ

Abstract

PURPOSE: In order to determine the effect of neuronal nitric oxide synthase(nNOS) in seizure-related neuronal vulnerability of the hippocampus, the expression patterns of nNOS were examined in pentylenetetrazole(PTZ)-induced seizure groups and in PTZ seizure groups which were pretreated with nNOS inhibitors.
METHODS
Male Sprague-Dawley rats weighing 200-300 g were used in PTZ(40 mg/kg)-induced seizure experiments. A specific inhibitor, 50 mg/kg 7-nitroindazole(7-NI), and a non-specific inhibitor, 50 mg/kg nitro-L-arginine(L-NA) were treated 30 min before the administration of PTZ to block nNOS. nNOS expression was evaluated by using immunohistochemical staining in the hippocampus of each group.
RESULTS
The onset time of the first myoclonic jerk was markedly delayed in the 7-NI and the L- NA pretreated groups in comparison to the PTZ group. In addition, 7-NI markedly suppressed the severity of PTZ-induced seizures. The expression of nNOS in the hippocampal CA3 area was higher than that in CA1 area in the PTZ treated groups. In the L-NA pretreated groups, the expression levels in the CA3 and CA1 areas were lower than those of the PTZ treated groups. Interestingly, in the 7-NI pretreated groups, the nNOS expression levels in CA1 and CA3 areas were makedly lower than those of PTZ and L-NA pretreated groups. There was no expression in CA2 area of all groups.
CONCLUSION
These results suggest that the hippocampal neurons expressing nNOS may be vulnerable to PTZ-induced seizures and that nNOS may play an important role in seizure-related neuronal vulnerability.

Keyword

Neuronal nitric oxide synthase; NOS inhibitor; Immunohistochemistry; Pentylenetetrazole; Seizure; Rat

MeSH Terms

Animals
Hippocampus*
Humans
Immunohistochemistry
Male
Myoclonus
Neurons*
Nitric Oxide
Nitric Oxide Synthase Type I*
Pentylenetetrazole
Rats*
Rats, Sprague-Dawley
Seizures*
Nitric Oxide
Nitric Oxide Synthase Type I
Pentylenetetrazole