European Journal of Histochemistry (Dec 2009)

Cytology of large neurons in the guinea pig dorsal cochlear nucleus contacting the inferior colliculus

  • L Alibardi

DOI
https://doi.org/10.4081/ejh.2000.1601
Journal volume & issue
Vol. 44, no. 4

Abstract

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Large neurons in the dorsal cochlear nucleus of the guinea pig which project to the inferior colliculus were identified after injections of the neural tracer WGA-HRP. Retrograde labelled cells (pyramidal and giant neurons) in the dorsal cochlear nucleus were glycine and GABA immunonegative and showed a similar ultrastructure. Between 30 and 60% of their perimeter was covered by axosomatic boutons, most of which (>50%) contained pleomorphic synaptic vesicles. Other boutons (about 40% of total) contained flat vesicles and few (5-6%) contained round vescicles, a characteristic of the excitatory cells innervating the inferior colliculus. Immunogold-cytochemistry, coupled to silver intensification, showed that more than 50% of axo-somatic pleomorphic boutons and over 90% of boutons containing flat and pleomorphic vesicles store glycine. Rare WGA-HRP labelled axo-somatic boutons containing flat-pleomorphic vesicles were seen on pyramidal and giant neurons. This suggests that a few inhibitory collicular terminals contact the excitatory large neurons in the dorsal cochlear nucleus.