Anticonvulsant and proconvulsant roles of nitric oxide in experimental epilepsy models

• Main Authors: Del-Bel E.A., Oliveira P.R., Oliveira J.A.C., Mishra P.K., Jobe P.C., Garcia-Cairasco N.
• Format: Article
• Language: English
• Published: Associação Brasileira de Divulgação Científica 1997-01-01
• Series: Brazilian Journal of Medical and Biological Research
• Subjects: experimental epilepsy; seizures; forebrain; brainstem; pilocarpine; pentylenetetrazol; audiogenic seizures; genetically epilepsy-prone rats; GEPR; nitric oxide
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000800010

The effect of acute (120 mg/kg) and chronic (25 mg/kg, twice a day, for 4 days) intraperitonial injection of the nitric oxide (NO) synthase (NOS) inhibitor NG-nitro-L-arginine (L-NOARG) was evaluated on seizure induction by drugs such as pilocarpine and pentylenetetrazole (PTZ) and by sound stimulation of audiogenic seizure-resistant (R) and audiogenic seizure-susceptible (S) rats. Seizures were elicited by a subconvulsant dose of pilocarpine (100 mg/kg) only after NOS inhibition. NOS inhibition also simultaneously potentiated the severity of PTZ-induced limbic seizures (60 mg/kg) and protected against PTZ-induced tonic seizures (80 mg/kg). The audiogenic seizure susceptibility of S or R rats did not change after similar treatments. In conclusion, proconvulsant effects of NOS inhibition are suggested to occur in the pilocarpine model and in the limbic components of PTZ-induced seizures, while an anticonvulsant role is suggested for the tonic seizures induced by higher doses of PTZ, revealing inhibitor-specific interactions with convulsant dose and also confirming the hypothesis that the effects of NOS inhibitors vary with the model of seizure