Characterization of tuberculo-ventral neurons in the dorsal cochlear nucleus of the guinea pig.

Tuberculo-ventral neurons in the deep polymorphic layer of the dorsal cochlear nucleus of the guinea pig are immunopositive to glycine, their main neurotransmitter, as revealed by post-embedding immunogold. The initial size of gold particles (10-20 nm) was increased (40-70 nm) by silver intensification for a better and rapid individuation of glycine positive cells at low magnification. The most specific ultrastructural characteristic of tuberculo-ventral neurons is their synaptic profile that shows most flat-pleomorphic axo-somatic boutons. This synaptic profile is different from that of other medium size neurons, such as cartwheel neurons in the superficial layer of the dorsal cochlear nucleus. The synaptic profile of tuberculo-ventral neurons together with other characteristics may explain their activity connected to the neural network responsible for echos suppression or/and sound localization.