Different effects of pentobarbital and pentylenetetrazol on nitric oxide levels in rat frontal cortex

Abstract

Levels of nitric oxide (NO) in the rat's frontal cortex were continuously monitored before and after intraperitoneal administration of an antiepileptic drug-pentobarbital (20 and 40 mg/kg) or convolsant drug - pentylenetetrazol (50 mg/kg). Pentobarbital decreased the levels of NO in a dose dependent manner. However, NO levels had a tendency to increase following the administration of pentylenetetrazol. It is suggested that central NO participates in the modulation of neuronal excitability, supporting the idea that NO is an important excitatory factor involved in the regulation of seizure susceptibility. Also, our results on anaesthetized rats suggests that endogenous NO may be involved in the mechanism of action of antiepileptic and analeptic drugs and this further suggest that NO levels in the human brain may decrease during antiepileptic therapy and increase during epileptic attacks or administration of excitatory drugs. The aim of the present study was to determine the possible role of NO levels in the brain during neuronal excitability and seizures.