Huntington’s chorea is a fatal degenerative condition inherited via sex chromosomes. It is rare in women who may carry the disease, which usually develops in middle-aged males. There is a gradual loss of mental and cognitive function, commonly associated with depression and progressive loss of voluntary motor control, leading to an increasing dependency on others.
The condition is incurable, although neuroleptic drugs such as haloperidol may be used to control symptoms. It has been suggested that the neuronal degeneration caused by the disease results from excess free-radicals oxidation or glutamate. Skaper et al showed cannabinoids, but not anandamide, to protect against glutamate-mediated neurotoxicity.
Peyser et al concluded "Antioxidant therapy may slow the rate of motor decline early in the course of Huntington's disease. " Hampson et al found THC and CBD to be ‘neuroprotective anti-oxidants’ improving the recovery prospects of stroke patients by reducing glutamate toxicity, and considered their results to suggest the neuroprotective action not to be receptor-dependent.
However Consroe et al found no positive or negative effect of CBD in Huntington’s patients, although this may be due to the degree of neuronal damage already present at the outset of the trial.
Richfield et al demonstrated there to be a selective loss of cannabinoid receptors in specific regions of the brain called the corpus striatum and globus pallidus, and Glass et al showed a ‘massive loss - 97.5%) of cannabinoid receptors in the substantia nigra (within spinal cord) of Huntington’s patients.
N-methyl-d-aspartate (NMDA) receptor antagonists have been shown to delay neurodegeneration, and a synthetic cannabinoid (+)-HU-210 has been found to be a potent antagonist of the NMDA receptor, ‘giving it a potential for use in ... neurodegenerative disorders’.
