Methyltetrahydrofolate as an antagonist of excitatory amino acids on spinal neurones.

Folate and N5-methyl-5,6,7,8-tetrahydrofolate (MTHF) have been reported to have excitatory effects upon cortical neurones, possibly due to interaction with kainate receptors. On spinal neurones these compounds have been found inactive as excitants; however MTHF is a weak antagonist of kainate and N-methyl-D-aspartate excitations, and less effectively blocks quisqualate also. It thus resembles the antagonist 2,3-piperidine dicarboxylate.