Kynurenine pathway and cognitive impairments in schizophrenia: Pharmacogenetics of galantamine and memantine

The Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) project designed to facilitate the development of new drugs for the treatment of cognitive impairments in people with schizophrenia, identified three drug mechanisms of particular interest: dopaminergic, cholinergic, and glutamatergic. Galantamine is an acetylcholinesterase inhibitor and a positive allosteric modulator of the α(7) nicotinic receptors. Memantine is an N-methyl-D-aspartate (NMDA) receptor antagonist. There is evidence to suggest that the combination of galantamine and memantine may be effective in the treatment of cognitive impairments in schizophrenia. There is a growing body of evidence that excess kynurenic acid (KYNA) is associated with cognitive impairments in schizophrenia. The α-7 nicotinic and the NMDA receptors may counteract the effects of kynurenic acid (KYNA) resulting in cognitive enhancement. Galantamine and memantine through its α-7 nicotinic and NMDA receptors respectively may counteract the effects of KYNA thereby improving cognitive impairments. The Single Nucleotide Polymorphisms in the Cholinergic Receptor, Nicotinic, Alpha 7 gene (CHRNA7), Glutamate (NMDA) Receptor, Metabotropic 1 (GRM1) gene, Dystrobrevin Binding Protein 1 (DTNBP1) and kynurenine 3-monooxygenase (KMO) gene may predict treatment response to galantamine and memantine combination for cognitive impairments in schizophrenia in the kynurenine pathway.