title: Review: cytological characteristics of commissural and tuberculo-ventral neurons in the rat dorsal cochlear nucleus.
abstract: The goal of the present review is to summarize the main ultrastructural and immunocytochemical characteristics for glycine and GABA in commissural (COM) and tuberculo-ventral neurons (TV) of the DCN. These neurons are localized in similar areas of the DCN multipolar but are connected to different targets. About 2/3rd of COM-neurons are large to bipolar neurons, mainly glycinergic, often GABA-ergic, with scarce ergastoplasm and axo-somatic boutons. About 1/3rd of COM-neurons are glycine and GABA-negative, and show little ergastoplasm and synaptic coverage. Occasional giant COM-neurons are glycine-positive and GABA-negative, and are covered with synaptic boutons. Other infrequent large neurons, rich in dense core vesicles, glycine- and GABA-negative, are most covered with boutons. TV-neurons are most glycinergic but 9% are glycine-negative. They have little ergastoplasm and a developed Golgi apparatus. Axo-somatic terminals are scarce and mainly contain flat and pleomorphic vesicles, glycine and sometimes GABA (inhibitory). TV-neurons receive a lower number of boutons than COM, which contain mainly flat-pleomorphic terminals. Putative COM-inhibitory boutons contact excitatory pyramidal and giant neurons (monosynaptic inhibition). Some putative inhibitory COM-terminals contact inhibitory cartwheel and tuberculo-ventral neurons. This indicates direct disinhibition and therefore excitation in the DCN (di-three-synaptic). Putative COM-mossy fibers reach the granule areas of the DCN, including unipolar brush cell dendrites, another possible excitatory commissural pathway.
authors.affiliation: Dipartimento di Biologia Evoluzionistica Sperimentale, Via Selmi 3, University of Bologna, 40126 Bologna, Italy. alibardi@biblio.cib.unibo.it
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Alibardi
mesh_terms: D000818:Animals; D017626:Cochlear Nucleus / Q000166:cytology*; D005998:Glycine / Q000032:analysis; D007150:Immunohistochemistry; D007395:Interneurons / Q000502:physiology / Q000648:ultrastructure; D009474:Neurons / Q000737:chemistry / Q000145:classification / Q000502:physiology / Q000648:ultrastructure*; D017729:Presynaptic Terminals / Q000145:classification / Q000502:physiology / Q000648:ultrastructure; D051381:Rats; D009435:Synaptic Transmission / Q000502:physiology; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D005680:gamma-Aminobutyric Acid / Q000032:analysis
chemical_list: D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D005680:gamma-Aminobutyric Acid; D005998:Glycine