gamma-Aminobutyric acid immunoreactivity in brainstem auditory nuclei of the chicken.

Using an antiserum directed against gamma-aminobutyric acid (GABA), the presence of presumed GABAergic neurons is demonstrated in the chicken auditory brainstem nuclei: nucleus laminaris, nucleus angularis, superior olive, and the ventral nuclei of the lateral lemniscus. Nucleus magnocellularis contains no immunopositive neurons but numerous GABA-positive terminals surrounding the cells. Terminal labeling is also present in the other auditory nuclei, though scarcer and not always associated with cell bodies. These data suggest an involvement of GABAergic inhibition in auditory processing in the lower auditory pathway of birds.