ELEVATED BRAIN GABA CORRELATES WITH SYSTEMIC DYSFUNCTIONS IN PAROXYSMAL CHICK

Altered brain GABA, phosphocreatine and adenosine triphosphate have be en documented in paroxysmal (px) chicks in earlier studies, suggesting perturbations in energy metabolism as a causative factor in this synd rome that is characterized by spontaneous neural degeneration of sever al central sensory systems, grand mal seizures, and progressive anorex ia. In this study, brain sections from 5-, 7-, and 10-day-old px and n ormal White Leghorn-cross chicks were stained by immunocytochemistry t o localize and quantify GABA. Serum glucose was measured to assess ade quacy of circulating energy substrate. Differences between px and norm al brains were found in GABA staining intensity in nuclei and tracts a ssociated with auditory, vestibular and oculomotor function, and in se veral septal areas. Staining appeared to be confined primarily to term inals, and increasingly larger numbers of stained terminals were found in older px brains. This progressive increase appears to parallel the degenerative changes that occur over time in px brain and progressive manifestation of clinical signs. Px chicks appear to have adequate ci rculating glucose, suggesting that alterations in brain energy substra tes are not a function of inadequate supply.