[Show abstract][Hide abstract] ABSTRACT: To study the changes of N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A) expression at local synapses in auditory cortices after early postnatal sound insulation and tone exposure.
We prepared highly purified synaptosomes from primary auditory cortex by Optiprep flotation gradient centrifugations, and compared the differences of NR2A expression in sound insulation PND14, PND28, PND42 and Tone exposure after sound insulation for 7 days by Western blotting.
The results showed that the NR2A protein expression of PND14 and PND28 decreased significantly (P<0.05). Tone exposure after sound insulation for 7 days, mSIe NR2A protein level increased significantly (P<0.05). It showed bidirectional regulation of NR2A protein. No significant effects of sound insulation and lone exposure were found on the relative expression level of NR2A of PND42 (P>0.05).
The results indicate that sound insulation and experience can modify the protein expression level of NR2A during the critical period of rat postnatal development. These findings provide important data for the study on the mechanisms of the developmental plasticity of sensory functions.
No preview · Article · Jun 2009 · Lin chuang er bi yan hou ke za zhi = Journal of clinical otorhinolaryngology
[Show abstract][Hide abstract] ABSTRACT: To investigate the mechanism of hearing pathway NMDAR regulating the changes of phosphorylated c-Jun expression in spiral ganglion after exposed Kunming mice to neural injury noise stimulation to induce permanent or temporary threshold shift.
To compare the different expressions of the key components (phosphorylated C-Jun) of NMDAR signal pathway during neural injury stimulation by Immunohistochemistry in CG.
The levels of phosphorylated c-Jun remarkably, increased in the spiral ganglion after 8 h, 48 h, 7 d and 14 d following noise trauma induced permanent threshold shift (PTS), and the numbers of positive cells reduced gradually. The similar changes occur in mice treated with MK-801 30 minutes before and after 3 h trauma induced PTS. After 48 h of noise induced TTS, the expression of Phosphorylated c-Jun return the level of normal control.
The expressions of phosphorylated c-Jun are time-related and uniform in the time and position in CG after noise trauma. MK-801 can alleviate the damage of noise trauma by altered the NMDA receptor-mediated calcium influx. Therefore, the NMDA receptors may involved in the damage of inner ear in common.
No preview · Article · Mar 2009 · Lin chuang er bi yan hou ke za zhi = Journal of clinical otorhinolaryngology