title: Ultrastructural characterization of gonadotropin-releasing hormone (GnRH)-immunoreactive terminal nerve cells in the dwarf gourami.
abstract: Recently we have been studying gonadotropin-releasing hormone (GnRH) cells of the terminal nerve (TN) in the dwarf gourami, which may serve as a good model system for the study of neuromodulator functions. Here we report on the ultrastructural characterization of TN-GnRH cells using postembedding immunoelectron microscopy. The GnRH immunoreactivities could be demonstrated on dense-cored vesicles (DCVs) in cell bodies, fibers and varicosities. However, we could find no evidence of GnRH-immunoreactive synapses which are characterized by active zones. This may suggest that GnRH is released non-synaptically from DCV-containing fiber varicosities and that it exerts its modulatory action on GnRH receptors located on nearby as well as distant target neurons.
authors.affiliation: Zoological Institute, Faculty of Science, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Oka
authors.forename: M
authors.initials: M
authors.lastname: Ichikawa
mesh_terms: D000818:Animals; D005260:Female; D005399:Fishes / Q000033:anatomy & histology*; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis*; D007150:Immunohistochemistry; D008297:Male; D016253:Microscopy, Immunoelectron; D009474:Neurons / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D007987:Gonadotropin-Releasing Hormone