Glutamate neurotoxicity to cochlear spiral ganglion cell in new born guinea pig

To examine glutamate neurotoxicity to spiral ganglion cell in new born guinea pigs by different administration approaches and different survival times. Glutamate was given by 2g/(kg·d) i.p., in the group(G21 0) for 21 days. the group (G7 14) and the group (G7 35) for 7 days. The results showed that the brainstem auditory evoked potential (BAEP) reaction thresholds were 65.3±21.5dB in group G21 0, 63.8±19.2dB in group G7 14 and 54.6±14.3dB in group G7 35. The density of ganglion cells was 1985.3±1021.7/mm 2, 3145.4±1225.3/mm 2 and 2990.4± 1022.1/mm 2 , respectively. It suggests that the degeneration of cochlea spiral ganglion cell is related to the duration of glutamate treatment. The degeneration can cause cell death but some of them showed a self limited process. Such pathologicel change are consistent with their acoustic ability during survival period.