Immunohistochemical study and an electron microscopic observation of the nucleus of the optic tract in the rat.
In the present study, gamma aminobutyric acid (GABA)-positive cells and terminals were detected in the nucleus of the optic tract (NOT) in the rat. However, GABA-positive cells in the NOT receiving projections directly from retinal ganglion cells could not be identified. To determine the role of GABA in the projection from the retinal ganglion cells to the NOT, we used electron microscopy to observe this nucleus of a rat in which one eyeball had been removed. In the nerve synapse binding region of the NOT on the side opposite to the enucleated eyeball, the symmetrical and asymmetrical types were recognized; the ratio between the two was the same as before the eyeball was enucleated. From these results, we conclude that the inhibitory axon terminals in the NOT do not have GABA activity. The GABA-positive cells seem to act indirectly as intrinsic interneurons, when processing or transmitting the information from the retina to the inferior olivary nucleus.
Sugano
S
S
Department of Otolaryngology, St. Marianna University School of Medicine, Kawasaki-shi, Japan.
Urushibata
T
T
Takeyama
I
I
D000818:Animals; D005260:Female; D007124:Immunoenzyme Techniques; D008854:Microscopy, Electron; D009411:Nerve Endings / Q000737:chemistry; D017120:Nystagmus, Optokinetic / Q000502:physiology; D009900:Optic Nerve / Q000648:ultrastructure*; D051381:Rats; D017208:Rats, Wistar; D012165:Retinal Ganglion Cells / Q000502:physiology / Q000648:ultrastructure*; D014795:Visual Pathways / Q000648:ultrastructure*; D005680:gamma-Aminobutyric Acid / Q000032:analysis* / Q000502:physiology
D005680:gamma-Aminobutyric Acid