Glutamine synthetase and glutamate metabolism in the guinea pig cochlea
| Autor: | M.D. Norenberg, Michel Eybalin, N. Renard |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Tissue Fixation
Guinea Pigs Fluorescent Antibody Technique Glutamic Acid Glutamate-glutamine cycle Biology Glutamate-Ammonia Ligase Glutamine synthetase otorhinolaryngologic diseases medicine Animals Frozen Sections Organ of Corti Spiral ganglion Cochlea Hair Cells Auditory Inner Glutaminase Glutamate receptor Vestibulocochlear Nerve Immunohistochemistry Sensory Systems Cell biology Hair Cells Auditory Outer Microscopy Electron Parvalbumins medicine.anatomical_structure Biochemistry Schwann Cells Tissue Preservation sense organs Hair cell Spiral Ganglion Neuroglia |
| Zdroj: | Hearing Research. 101:93-101 |
| ISSN: | 0378-5955 |
| DOI: | 10.1016/s0378-5955(96)00136-0 |
| Popis: | Glutamate is thought to act as a neurotransmitter of the sensory hair cells of the organ of Corti. Glutamine synthetase could be involved in a type of glutamate-glutamine cycle in the cochlea which could clear glutamate off the synaptic cleft and replenish the hair cell glutamate neurotransmitter store. Using both light and electron microscopic immunocytochemistry to localize this enzyme in the guinea pig cochlea, we have observed immunoreactive satellite glial cells surrounding parvalbumin-immunoreactive primary auditory neurons in the spiral ganglion. Glutamine synthetase was also detected in Schwann cells of the osseous spiral lamina which form the myelin sheath of nerve fibers. On the contrary, no immunoreactivity could be observed in the cochlear nerve and in the organ of Corti, although this organ contains structures able to take up glutamate. Although they confirm earlier works involving glutamine synthetase in the conversion of L-[3H]glutamate taken up by glial cells, our results suggest that the cochlear glutamate-glutamine cycle is not primarily involved in the recycling and replenishment of hair cell neurotransmitter glutamate. Alternatively, it is proposed that glutamine synthetase functions to limit the perilymphatic glutamate concentrations. |
| Databáze: | OpenAIRE |
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