Epilepsy, CNS viral injury and dynorphin.

Epilepsy is a significant health problem. Despite the widespread use of both classic and newer pharmacological agents that target ion channels, amino acid transmission or receptors, there are numerous examples of mono- or polytherapy being ineffective. Seizures that are secondary to CNS infections are among the most refractory medically, and thus insult-specific agents are desirable. Recently, the study of the neuropharmacological actions of dynorphin in CNS viral injury has yielded new insights into epileptogenesis and epilepsy treatment. The opioid neuropeptide dynorphin modulates neuronal excitability in vitro in hippocampal slices and potentiates endogenous anti-ictal (i.e. protective) processes in animal models and humans. This work has renewed interest in the role of dysregulation of dynorphin in the pathogenesis of refractory seizures, including encephalitic seizures. The important role of dynorphin in epilepsy is also supported by new models of symptomatic epilepsies based on viral-induced seizures.