Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Epilepsy is a class of disorders characterized by seizures attributable to abnormal, synchronous neural activity in the brain. While the underlying etiology of epilepsy is usually unknown, much work has been devoted to the prevention or control of seizure activity. Currently, pharmacological intervention is the most effective and prevalent strategy for the treatment of epilepsy. While there has been a plethora of research conducted on the efficacy of anticonvulsant compounds, many of the side effects due to maintenance on these drugs have not been adequately investigated. One such side effect involves the reported impairment in mental processing associated with antiepileptic drug treatment. It has been repeatedly suggested that while seizure activity can profoundly impair learning abilities, maintenance on anticonvulsant drugs themselves can potentiate these impairments. In agreement with these suggestions, we have previously reported learning impairments in rats and rabbits in instrumental and Pavlovian conditioning tasks respectively (e.g., Churchill et al., 1998).

While progress has been made on determining the relative cognitive side effects associated with antiepileptic drug therapy, there are many more questions regarding these issues that have not been adequately addressed. In this study, we have evaluated the effects of maintenance on four of the most frequently prescribed anticonvulsant drugs in rats performing in a Morris water maze escape task. Successful mastery of the Morris water maze has been shown to be dependent upon normal hippocampal (Morris et al., 1982) and frontal cortical functioning Compton et al., 1997; de Bruin et al., 1997), and upon intact N-methyl-D-aspartate (NMDA) receptors (Morris et al., 1986). If deficits in performance due to maintenance on these drugs, as we have previously reported for phenytoin using both classical and instrumental tasks, are due to actions in the hippocampus and/or prefrontal cortex, then rats treated with these compounds should be impaired in the water maze task as well.

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