title: Glutamate-like immunoreactivity in retinal terminals in the nucleus of the optic tract in rabbits.
abstract: The ultrastructural organization of retinal terminals within the nucleus of the optic tract of rabbits was investigated with a combination of anterograde tracing and immunocytochemistry. The anterogradely transported WGA-HRP injected in the vitreous of the eye was visualized with the sensitive gold-substituted silver peroxidase (GSSP) method. Glutamate and GABA immunoreactivity were identified with postembedding colloidal gold particles. Retinal ganglion cell terminals (R-terminals) in the nucleus of the optic tract formed asymmetric synapses and contained spherical vesicles and electron lucent mitochondria. R-terminals were observed in large clusters in the neuropil and in synaptic contact with large initial dendrites and somata. Within the clusters of neuropil the R-terminals formed two types of glomeruluslike arrangements: (1) an R-terminal centrally located and surrounded by small dendritic and axonal profiles and (2) several R-terminals surrounding a single dendrite or a group of dendritic profiles, presumably of interneuronal origin. All R-terminals identified with WGA-HRP as well as those exhibiting similar ultrastructural characteristics showed high levels of glutamate immunoreactivity, but no GABA immunoreactivity. The presence of glutamate and the absence of GABA in R-terminals suggest that glutamate is involved in neurotransmission in the pathway from retina to the nucleus of the optic tract of rabbits.
authors.affiliation: Department of Morphology, The Netherlands Ophthalmic Research Institute, Amsterdam.
authors.forename: B N
authors.initials: BN
authors.lastname: Cardozo
authors.forename: R
authors.initials: R
authors.lastname: Buijs
authors.forename: J
authors.initials: J
authors.lastname: Van der Want
mesh_terms: D000818:Animals; D001370:Axonal Transport; D001369:Axons / Q000648:ultrastructure; D005971:Glutamates / Q000032:analysis*; D018698:Glutamic Acid; D006735:Horseradish Peroxidase; D007124:Immunoenzyme Techniques; D008297:Male; D016253:Microscopy, Immunoelectron; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D011817:Rabbits; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000648:ultrastructure*; D013477:Superior Colliculi / Q000648:ultrastructure; D013569:Synapses / Q000648:ultrastructure*; D014795:Visual Pathways / Q000033:anatomy & histology / Q000648:ultrastructure*; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
chemical_list: D005971:Glutamates; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D006735:Horseradish Peroxidase