Ultrastructural localization of glutamate and aspartate immunoreactivities in gerbil inner hair cells.
The endogenous neurotransmitter released at the base of cochlear inner hair cells (IHCs) is still not clear. L-Glutamate is the most likely candidate at present. Although it has been demonstrated that IHCs contain high levels of glutamate, the association of glutamate with synaptic release has not yet been established. In this study, presynaptic location of glutamate and aspartate immunoreactivities was examined by using the postembedding immunogold technique. The results show that neither glutamate nor aspartate exhibit immunoreactivities around the synaptic vesicles of IHCs. Although the results do not support the hypothesis that glutamate or aspartate is the endogenous neurotransmitter, the possibility that the real transmitter is a substance with a structure very similar to glutamate or aspartate cannot be excluded.
Liu
T C
TC
Department of Otolaryngology, School of Medicine, National Taiwan University, Taipei.
D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry*; D005849:Gerbillinae; D018698:Glutamic Acid / Q000737:chemistry*; D006198:Hair Cells, Auditory / Q000648:ultrastructure*; D007150:Immunohistochemistry; D008854:Microscopy, Electron
D001224:Aspartic Acid; D018698:Glutamic Acid