Synaptophysin immunoreactivity in the cochlear nuclei of mammals: a comparative study

Synaptophysin is a Ca(2+)-binding glycoprotein located in the presynaptic membrane and synaptic vesicles. This glycoprotein has been also involved in the release of neurotransmitters. The presence of synaptophysin within the cochlear nuclear complex of several animal species was analyzed. Differences in size and neuronal density of the cochlear nuclei were observed between the animal species studied. In fact, cat and rat cochlear nuclei showed a very similar morphology and neuronal distribution, while mouse, hamster and guinea pig exhibited important differences. The morphology and arrangement of synaptic boutons, for each neuronal type considered, were similar among species.