An antagonist drug is one that opposes the action on the nervous system of a substance occurring naturally in the body by combining with and blocking its nervous receptor. The theory that blocking NMDA receptors will help HD seems to be wrong. The theory has not been sufficiently investigated in mice. Dextromethorphan is a NMDA blocker and is sold OTC as a cold remedy and should be avoided by HD folks.

Amantadine , riluzole and remacemide are NMDA blockers. HD patients are in trials of NMDA blockers. Other patients are being recruited for NMDA blocker trials. Here is good evidence that NMDA blockers may accelerate neuronal death. --Jerry 11/02/00
Adapted from: Proc Natl Acad Sci U S A 2000 Oct 31,Ikonomidou C., et al.

Glutamate promotes neuronal survival during brain development and destroys neurons after injuries in the mature brain.

Glutamate antagonists are in human clinical trials aiming to demonstrate limitation of neuronal injury after head trauma, which consists of both rapid and slowly progressing neurodegeneration. Furthermore, glutamate antagonists are considered for neuroprotection in chronic neurodegenerative disorders with slowly progressing cell death only. Therefore, humans suffering from Huntington's disease, characterized by slowly progressing neurodegeneration of the basal ganglia, are subjected to trials with glutamate antagonists.

Here we demonstrate that progressive neurodegeneration in the basal ganglia induced by the mitochondrial toxin 3-nitropropionate or in the hippocampus by traumatic brain injury is enhanced by N-methyl-d-aspartate antagonists but ameliorated by alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate antagonists.

These observations reveal that N-methyl-d-aspartate antagonists may increase neurodestruction in mature brain undergoing slowly progressing neurodegeneration, whereas blockade of the action of glutamate at alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate receptors may be neuroprotective.