To investigate the glutamate-like immunoreactivity (Glu-IR) changes in inner hair cells (IHCs) of guinea pigs cochlear after noise exposure. Guinea pigs were distributed into 6 groups including control group (g1), and...To investigate the glutamate-like immunoreactivity (Glu-IR) changes in inner hair cells (IHCs) of guinea pigs cochlear after noise exposure. Guinea pigs were distributed into 6 groups including control group (g1), and groups of immediately (g2), 8 hours (g3), 1 day (g4), 3 days (g5) and 7days (g6) after noise exposure. The experimental groups were exposed to 120 dBLp 1/3 octave 4 kHz narrow band noise for 4 hours to ruin the organ of Corti. The first turn of the organ of Corti was dissected to make ultrathin sections and under went immunoelectron study. The density of gold particles of Glu-IR in IHCs was measured. Results showed that Glu-IR in IHCs after noise exposure changed dynamically. The density of gold particle in IHCs of g2 significantly increased (p < 0.001) compared with gl and decreased in g3 (p < 0.001), whereas there were no significant difference in the groups of g4, g5 and g6 (p > 0.05). The results suggest that there may be glutamate autoreceptors in the membrane of IHCs and the glutamate released from pre-synapse may act on these autoreceptors in a postitive feedback manner, which induced [Ca2+] increased in IHCs immediately after noise exposure. Glutamate synthetase system was activated by Ca2+ and more glutamic acid was produced. In the group of 8 hours after noise exposure, glutamic acid decreased in IHCs because of its over-releasing into synapses. Glu-IR's recovery to normal level indicated that the glutamate-glutamine cycle may exist in guinea pig cochlea.展开更多
基金This work was supported by the National Natural Science Foundation of China (39870797).
文摘To investigate the glutamate-like immunoreactivity (Glu-IR) changes in inner hair cells (IHCs) of guinea pigs cochlear after noise exposure. Guinea pigs were distributed into 6 groups including control group (g1), and groups of immediately (g2), 8 hours (g3), 1 day (g4), 3 days (g5) and 7days (g6) after noise exposure. The experimental groups were exposed to 120 dBLp 1/3 octave 4 kHz narrow band noise for 4 hours to ruin the organ of Corti. The first turn of the organ of Corti was dissected to make ultrathin sections and under went immunoelectron study. The density of gold particles of Glu-IR in IHCs was measured. Results showed that Glu-IR in IHCs after noise exposure changed dynamically. The density of gold particle in IHCs of g2 significantly increased (p < 0.001) compared with gl and decreased in g3 (p < 0.001), whereas there were no significant difference in the groups of g4, g5 and g6 (p > 0.05). The results suggest that there may be glutamate autoreceptors in the membrane of IHCs and the glutamate released from pre-synapse may act on these autoreceptors in a postitive feedback manner, which induced [Ca2+] increased in IHCs immediately after noise exposure. Glutamate synthetase system was activated by Ca2+ and more glutamic acid was produced. In the group of 8 hours after noise exposure, glutamic acid decreased in IHCs because of its over-releasing into synapses. Glu-IR's recovery to normal level indicated that the glutamate-glutamine cycle may exist in guinea pig cochlea.
