ABSTRACT
Guanosine 3',5 monophosphate [cGMP] can be used as a marker of the epileptogenicity of proconvulsant drugs. As valproic acid [VPA], at certain concentrations, acts as a proconvulsant agent in hippocampal pyramidal neurons when tested in the veratridine model, this investigation was conducted to study the effect of proconvulsant concentrations of VPA on the basal level of cGMP in hippocampal tissue. Experiments were performed using standard radioimmuonassay techniques in hippocampal tissues from rats. This study was carried out at the Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas, United States of America between 1996-1997. We found that veratridine [0.3, 1 and 2 micro M, n=3] increased the level of cGMP in hippocampal tissue in a concentration dependent manner. However, VPA at proepileptic concentrations [0.1, 2, 5 micro M, n=3], did not significantly affect the basal level of cGMP when added alone or with veratridine [0.3 micro M]. Guanosine 3',5' monophosphate is not a marker of the proepileptic activity of VPA in brain tissues