The role of NPY in seizure control and weight gain when valpoic acid is used by epilepsy patients.

Abstract

The role of NPY in seizure control and weigh gain when valproic acid is used by epileptic patients

Aims: That weight gain is one of the concerning side effects of valproic acid (VPA) is confirmed repeatedly in convincing studies. VPA is mainly used by epileptic patients and been available on the market for many years. VPA suppresses susceptibility to seizures. However, the underlying mechanism of it and why it induces weight gain remains unknown. Several hypotheses have been suggested to explain the observed effects of VPA. This thesis focuses on one of these hypotheses, namely the role of neuropeptide Y (NPY) in VPA-induced weight gain. We hypothesized that VPA induce weight gain by increasing the levels of NPY.

Methods: Initially, the role of NPY in seizure control is elaborated. Subsequently, the role of NPY in energy homeostasis is described. In the third chapter we attempt to make a link between VPA and NPY. Finally, other possible hypotheses to explain VPA-induced weight gain are discussed.

Results: NPY is a neuropeptide that mainly functions in the brain. NPY is involved in seizure control and energy homeostasis. In seizure control NPY reduces susceptibility to seizures. In energy homeostasis it increases appetite and thereby food intake. NPY levels are enhanced after starting with VPA. However, measurements were done several months after starting the VPA-therapy. In addition, the levels of other neuronal peptides and hormones were changed.

Conclusion: Because NPY plays a role in both seizure and weight control, NPY is a possible candidate for the link between VPA and weight gain. However, it is difficult to establish if VPA is affecting NPY directly or indirectly. Changes in NPY levels could also be a secondary consequence of VPA therapy and more hypotheses could be mentioned to explain VPA-induced weight gain. Therefore, more research is needed to investigate these hypotheses.