In mammals,the ribbon synapses of cochlear inner hair cells are a synaptic structure of the first sensory nerve in the pathway of acoustical signal transmission to the acoustic center,and it is directly involved in vo...In mammals,the ribbon synapses of cochlear inner hair cells are a synaptic structure of the first sensory nerve in the pathway of acoustical signal transmission to the acoustic center,and it is directly involved in voice coding and neurotransmitter release. It is difficult to quantitatively analyze the ribbon synaptic number only using an electron microscope,because the ribbon synaptic number is relatively limited and their location is deep. In this study,the specific presynaptic structure-RIBEYE,and non-specific postsynaptic structure-GluR 2 & 3 in C57BL/6J mouse basilar membrane samples were treated by immunofluorescent labeling. Serial section was performed on the samples using a laser scanning confocal microscope,and then the serial sections were used to build three-dimensional models using 3DS MAX software. Each fluorescein color pair indicates one synapse,so the number of ribbon synapses of inner hair cells is obtained. The spatial distribution and the number of ribbon synapses of cochlear inner hair cells were clearly shown in this experiment,and the mean number of ribbon synapses per inner hair cell was 16.10±1.03. Our results have demonstrated the number of ribbon synapses is accurately calculated by double immunofluorescent labeling to presynaptic and postsynaptic structures,serial sections obtained using a laser scanning confocal microscope,and three-dimensional modeling obtained using 3DS MAX software. The method above is feasible and has important significance for further exploring the mechanism of sensorineural deafness.展开更多
Compound action potentials (CAP) and action potential-summating potential complex (AP-SP) evoked by click and tone burst respectively were recorded from the round window in guinea pigs. Correlations between the positi...Compound action potentials (CAP) and action potential-summating potential complex (AP-SP) evoked by click and tone burst respectively were recorded from the round window in guinea pigs. Correlations between the positive and negative summating potentials (SP+ and SP-) were examined before and after impulse sound exposure. The results show that the SP- is related to the threshold shift of CAP. In comparison to normal condition, it appears with a high incidence when the auditory threshold shift reaches 30 dB or more. SP-increases in amplitude when SP+ decreases. The smaller the amplitude of SP+, the larger that of SP-. This suggests that in normal hearing condition SP- may be suppressed by SP+. Such suppression may be released if OHCs are injured. The dominant SP- as a sign of recruitment may be due to the change in the nonlinear character of IHC following OHC damage.展开更多
文摘In mammals,the ribbon synapses of cochlear inner hair cells are a synaptic structure of the first sensory nerve in the pathway of acoustical signal transmission to the acoustic center,and it is directly involved in voice coding and neurotransmitter release. It is difficult to quantitatively analyze the ribbon synaptic number only using an electron microscope,because the ribbon synaptic number is relatively limited and their location is deep. In this study,the specific presynaptic structure-RIBEYE,and non-specific postsynaptic structure-GluR 2 & 3 in C57BL/6J mouse basilar membrane samples were treated by immunofluorescent labeling. Serial section was performed on the samples using a laser scanning confocal microscope,and then the serial sections were used to build three-dimensional models using 3DS MAX software. Each fluorescein color pair indicates one synapse,so the number of ribbon synapses of inner hair cells is obtained. The spatial distribution and the number of ribbon synapses of cochlear inner hair cells were clearly shown in this experiment,and the mean number of ribbon synapses per inner hair cell was 16.10±1.03. Our results have demonstrated the number of ribbon synapses is accurately calculated by double immunofluorescent labeling to presynaptic and postsynaptic structures,serial sections obtained using a laser scanning confocal microscope,and three-dimensional modeling obtained using 3DS MAX software. The method above is feasible and has important significance for further exploring the mechanism of sensorineural deafness.
文摘Compound action potentials (CAP) and action potential-summating potential complex (AP-SP) evoked by click and tone burst respectively were recorded from the round window in guinea pigs. Correlations between the positive and negative summating potentials (SP+ and SP-) were examined before and after impulse sound exposure. The results show that the SP- is related to the threshold shift of CAP. In comparison to normal condition, it appears with a high incidence when the auditory threshold shift reaches 30 dB or more. SP-increases in amplitude when SP+ decreases. The smaller the amplitude of SP+, the larger that of SP-. This suggests that in normal hearing condition SP- may be suppressed by SP+. Such suppression may be released if OHCs are injured. The dominant SP- as a sign of recruitment may be due to the change in the nonlinear character of IHC following OHC damage.
