These findings suggest that human IFN-alpha has a greater potential for inducing increase of the immobility in the rat forced swimming test than human IFN-beta and -gamma, and that the effect of human IFN-alpha might not be mediated through IFN-alpha/beta receptors.

1 We investigated the mechanism by which human interferon-a (IFN-a) increases the immobility time in a forced swimming test, an animal model of depression. 2 Central administration of IFN-a (0.05 ± 50 IU per mouse, i.cist.) increased the immobility time in the forced swimming test in mice in a dose-dependent manner.

Summary:Purpose: Nefiracetam (NEF) is a novel pyrrolidone-type nootropic agent, and it has been reported to possess various pharmacologic effects as well as cognitionenhancing effects. The present study focused on the anticonvulsant effect of NEF and its potential for antiepileptic therapy.Methods: The anticonvulsant properties of NEF were investigated in experimental seizure models of mice and rats, compared with levetiracetam (LEV) and other standard antiepileptic drugs [AEDs; zonisamide (ZNS), phenytoin (PHT), carbamazepine (CBZ), valproic acid (VPA), diazepam (DZP), and ethosuximide (ESM)]. With reference to standard programs for evaluating potential AEDs, the study included the traditional maximal electroshock seizure and subcutaneous chemoconvulsant (pentylenetetrazole, bicuculline, picrotoxin, strychnine, or N-methyl-D-aspartate) seizure tests and two threshold models (the increasing-current electroshock seizure test and intravenous pentylenetetrazole seizure threshold test). Neurotoxic activities were examined with the rotarod test and traction test.Results: NEF inhibited electroshock-induced seizures at nontoxic doses, whereas it had no effect on seizures chemically induced by pentylenetetrazole, bicuculline, picrotoxin, strychnine, or N-methyl-D-aspartate. The anticonvulsant spectrum of NEF paralleled that of ZNS, PHT, and CBZ. The anticonvulsant efficacy of NEF was comparable with that of ZNS and less potent than that of PHT, CBZ, and DZP. However, the safety margin of NEF was superior to that of ZNS, CBZ, VPA, and DZP. LEV showed only slight anticonvulsant effects in threshold models, and it was not effective in conventional screening models.Conclusions: These results suggest that NEF has distinct anticonvulsant spectrum and mechanisms from those of LEV. NEF is an orally active and safe AED, and it possesses a potential for antiepileptic therapy. Key Words: NefiracetamLevetiracetam-Nootropic-Seizure-Antiepileptic.Cognition-enhancing agents (or nootropics) are drugs used for the treatment of impaired brain function resulting from cerebral deficiencies such as senile dementia or cerebral vascular disorders (1-3). Nefiracetam [NEF; N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl)acetamide, DM-9384] is a novel pyrrolidone-type nootropic and has been reported to enhance learning acquisition and to improve experimentally induced amnesia in various animal models (4-7). Electrophysiologic and neurochemical studies have demonstrated that NEF activates N/L-type Ca 2+ channels (8,9), and cholinergic, monoaminergic and γ -aminobutyric acid (GABA)ergic systems (10-15).Some pyrrolidone derivatives such as piracetam and oxiracetam have been reported to possess anticonvulsant activities (16) or synergistic effects in combination with antiepileptic drugs (AEDs) (17,18). Piracetam has been Accepted February 6, 2005. Address correspondence and reprint requests to Dr. Y. Kitano at New Product Research Laboratories II, Daiichi Pharmaceutical Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan. E-mail: kitanpm...

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