GABA immunoreactivity in the primary nuclei of the auditory central nervous system

Structures containing gamma-amino butyric acid (GABA) were investigated in the guinea pig cochlear nuclei and superior olivary complexes by means of an immunohistochemical procedure using an antibody directed against GABA. Immunoreactivity was observed in cell bodies of the superficial layers of the ventral and dorsal cochlear nuclei, in lateral superior olive, in some neurons of the medial superior olive, in lateral preolivary nuclei and in the lateral nucleus of the trapezoid body. Fibers and profiles exhibiting GABA immunoreactivity were found in almost all regions of the lower auditory pathways. The abundance of GABA in these regions indicates an important role of this inhibitory amino-acid in the auditory brainstem.