L-pyroglutamate: an alternate neurotoxin for a rodent model of Huntington's disease

Intrastriatal injections of L-Pyroglutamate (L-PGA) in mice produced behavioral and neuropathological effects that resemble in part the kainate-injected rat striatal model of Huntington's Disease (HD). The behavioral responses induced after unilateral injections of L-PGA included circling, postural asymmetry of head and trunk and possible dyskinesias. The neuropil in the injected striatum contained dilated profiles, degenerating neurons and oligodendroglia, and numerous phagocytic microglial-like cells. A dose response relation existed. The size of the lesion (expressed as a percent volume of the striatum destroyed) ranged from 1 +/- 0.18% at 0.02 mumoles to 20.2 +/- 3.97% at 200 mumoles L-PGA (pH = 7.3). L-PGA is a weak neurotoxin when compared to kainic acid. Several factors raise interest in the possible role of L-PGA in HD, including the recently reported elevated plasma levels of L-PGA in some HD patients, and these considered in the discussion.