The involvement of serotonin (5-hydroxytryptamine) in photosensitive epilepsy

Over the last decade, vigorous efforts have been made by neuroscientists to unravel the cellular and molecular basis of photosensitive Epileptogenic activities in the central nervous system (CNS). Many neurotransmitters are implicated in brain activities but the extent to which they participate in these activities needs to be clarified. This review discusses the involvement of serotonin (5-hydroxytryptamine, 5-HT) in photosensitive epilepsy. The biosynthesis, metabolism, and structural and functional distribution of serotonin in the brain, and the role of 5-HT, its precursors, metabolites, receptors, agonists, antagonists, and the enzymes of reaction in photosensitive epileptogenic activity with reference to 5-HT cortical density, are discussed. The effects of biosynthetic and metabolic impairments in the serotonergic system, and the extent to which they contribute to the elicitation of myoclonic phenomena, hallucination, impulsivity, and migraine (HIMM) in photosensitive epilepsy are critically reviewed, and supported by evidence from animal models of photosensitive epilepsy. This evidence is correlated with the clinical findings in human photosensitive epilepsy.