Excitotoxicity and the kynurenine pathway in multiple sclerosis

This chapter will focus on the contribution of excitotoxicity to neurodegeneration in the context of multiple sclerosis (MS). MS has long been regarded as an autoimmune inflammatory disease of the central nervous system (CNS). Recent advances in the literature now acknowledge a larger contribution of neurodegeneration inherent to the disease process that goes beyond merely oligodendrocytes as targets of an autoimmune response. In particular, this section will highlight the effects of excitotoxic mechanisms involving glutamate and the tryptophan catabolic, quinolinic acid, on important components in the immune system such as oligodendrocytes, astrocytes, and microglia. Herein, a brief overview will be provided on how various aspects of excitotoxicity are evident in MS pathology and its possible roles between interactions of cells in the CNS that ultimately lead to neurodegeneration in inflammatory condition of MS.