目的研究miRNA-34a、沉默信息调节因子(Silent information regulator,SIRT6)对老龄小鼠听觉皮层神经元细胞凋亡的影响及机制。方法miRNA-34a基因敲除小鼠(miRNA-34a敲除组)、SIRT6基因敲除小鼠(SIRT6敲除组)与野生型小鼠(对照组)各10只...目的研究miRNA-34a、沉默信息调节因子(Silent information regulator,SIRT6)对老龄小鼠听觉皮层神经元细胞凋亡的影响及机制。方法miRNA-34a基因敲除小鼠(miRNA-34a敲除组)、SIRT6基因敲除小鼠(SIRT6敲除组)与野生型小鼠(对照组)各10只,所有小鼠均为16月龄,TUNEL法分别检测各组小鼠听觉皮层神经元细胞凋亡情况,免疫组化法检测各组小鼠听觉皮层神经元中B细胞淋巴瘤-2(B-cell lymphoma-2,Bcl-2)、Bcl-2相关的x蛋白(B-cell lymphoma-2 associated X protein,Bax)、半胱氨酸天冬氨酸蛋白酶8(Cysteine aspartic protease8,Caspase8)、半胱氨酸天冬氨酸蛋白酶3(Cysteine aspartic protease3,Caspase3)表达情况。结果miRNA-34a敲除组小鼠听觉皮层神经元细胞凋亡指数与SIRT6组相比,差异有统计学意义(P<0.05),miRNA-34a敲除组与对照组相比,差异无统计学意义(P>0.05),SIRT6敲除组与对照组相比,差异有统计学意义(P<0.05);miRNA-34a敲除组小鼠听觉皮层神经元抑凋亡因子Bcl-2表达量与SIRT6敲除组相比,差异有统计学意义(P<0.05),miRNA-34a敲除组与对照组相比,差异无统计学意义(P>0.05),SIRT6敲除组与对照组相比,差异有统计学意义(P<0.05);miRNA-34a敲除组小鼠听觉皮层神经元促凋亡因子Bax、Caspase8、Caspase3表达量与SIRT6敲除组相比,差异有统计学意义(P<0.05),miRNA-34a敲除组与对照组相比,差异无统计学意义(P>0.05),SIRT6敲除组与对照组相比,差异有统计学意义(P<0.05)。结论miRNA-34a与SIRT6可通过多种凋亡因子调控老龄小鼠听觉皮层神经元细胞凋亡过程;miRNA-34a促进其凋亡,而SIRT6抑制小鼠听觉皮层神经元细胞凋亡;miRNA-34a与SIRT6在调控小鼠听觉皮层神经元凋亡中负相关,二者可能是治疗老年性耳聋的新靶点。展开更多
目的研究动物处于不同行为状态时,纹状体听觉神经元对声音信息的特征表达是否被调控。方法以SPF级C57BL/6J清醒小鼠纹状体的听觉神经元为研究对象,通过搭建同步的在体电生理和运动记录系统,采用玻璃微电极贴附式记录方法长时间记录纹状...目的研究动物处于不同行为状态时,纹状体听觉神经元对声音信息的特征表达是否被调控。方法以SPF级C57BL/6J清醒小鼠纹状体的听觉神经元为研究对象,通过搭建同步的在体电生理和运动记录系统,采用玻璃微电极贴附式记录方法长时间记录纹状体听觉神经元对噪声的听觉响应,并通过分析小鼠跑动速度将小鼠的行为状态分为安静状态和运动状态,分析动物处于两种行为状态下纹状体听觉神经元的自发活动和诱发响应。结果相对于安静状态,当动物处于运动状态时,纹状体听觉神经元的自发活动增高(37.06±12.02 vs 18.51±10.91,P<0.001),而诱发响应下降(噪声强度=60 dB,3.45±2.99 vs 3.04±2.76,P<0.001)。结论运动状态对纹状体的听觉响应具有显著的抑制作用,这可能是导致运动状态时声音信息的识别能力下降的重要原因。展开更多
本刊开办异或新虹栏目,旨在每期介绍一位在海外定居,学有成就的华裔学者,他们将介绍国外最新的临床、科研动态,同时欢迎对国内专业发展提出建设性意见,畅所欲言,批评争鸣,以诚恳求实的治学态度与国内同仁同道共勉。同时借本栏目广招天...本刊开办异或新虹栏目,旨在每期介绍一位在海外定居,学有成就的华裔学者,他们将介绍国外最新的临床、科研动态,同时欢迎对国内专业发展提出建设性意见,畅所欲言,批评争鸣,以诚恳求实的治学态度与国内同仁同道共勉。同时借本栏目广招天下饱学贤良之才,热情杂志建设之士,共办《Jounal of Otology》,为促进国际间合作搭建一个学术交流的平台,有效快速地将中国不断发展的耳科学成果向世界展示,欢迎广大海外学者积极投稿。展开更多
A sustained monaural block of auditory air-conduction model was established in rats through subcutaneous suture in the right ear canal.The gene expression levels of hypothalamic N-methyl-D-aspartate receptor NR1,NR2A,...A sustained monaural block of auditory air-conduction model was established in rats through subcutaneous suture in the right ear canal.The gene expression levels of hypothalamic N-methyl-D-aspartate receptor NR1,NR2A,NR2B and NR2C mRNA in the auditory central nervous system of Sprague-Dawley rats at postnatal 9,23,37 days were determined after an environmental change.Reverse transcription-PCR assay showed that the critical period for the development of NR1,NR2A,and NR2B subunits in the left hypothalamus and NR1-and NR2B-dependent auditory neurons in the right hypothalamus terminated 23 days after the suture in the right ear.The critical period for the development of NR2A subunit-dependent auditory neurons in the right hypothalamus was terminated by postnatal day 37.The results confirmed that N-methyl-D-aspartate receptor subunits in the hypothalamus may be regulated by the auditory environment.展开更多
In this study, we investigated the features of latency-amplitude (L-A) functions at different sound frequencies, using extracellular recording from auditory neurons in the central nucleus of the inferior colliculus (I...In this study, we investigated the features of latency-amplitude (L-A) functions at different sound frequencies, using extracellular recording from auditory neurons in the central nucleus of the inferior colliculus (ICC) in mice. Isofrequency L-A functions from single neurons could be fit with a newly developed equation based on Pieron's law. The high degree of fitness indicates that the curvatures of all isofrequency L-A functions for a given neuron are similar, and that the difference between L-A functions is due to a shift in their positions in the coordinate system. When we normalized the L-A functions to match the position of the L-A function obtained at the neuronal characteristic frequency (CF), all isofrequency L-A functions from a given ICC neuron were highly superimposed. The similar shapes of the L-A functions at different frequencies may reflect the physical laws of sound being transferred into bioelectric signals. The position of a non-CF L-A function could be measured as the differences of the asymptotic L and A ( L and A) compared to the L-A function at a reference frequency such as the CF. The nerve fibers and synapses connecting to a neuron for acoustic information processing can be functionally simplified as a single "wire" (as the total length of nerve fibers) and "joint" (as the summated size/strength of synapses). The wire and joint mediate information transmission and transduction, respectively. Thus, L and A may be measurements of the total length of nerve fibers and the strength of summated synapses in the activated auditory pathway. L and A differed between frequency channels and neurons, suggesting that the differences of acoustic neuronal responses are always caused by activation of different pathways, and that the pathways that process sounds are diverse.展开更多
文摘目的研究动物处于不同行为状态时,纹状体听觉神经元对声音信息的特征表达是否被调控。方法以SPF级C57BL/6J清醒小鼠纹状体的听觉神经元为研究对象,通过搭建同步的在体电生理和运动记录系统,采用玻璃微电极贴附式记录方法长时间记录纹状体听觉神经元对噪声的听觉响应,并通过分析小鼠跑动速度将小鼠的行为状态分为安静状态和运动状态,分析动物处于两种行为状态下纹状体听觉神经元的自发活动和诱发响应。结果相对于安静状态,当动物处于运动状态时,纹状体听觉神经元的自发活动增高(37.06±12.02 vs 18.51±10.91,P<0.001),而诱发响应下降(噪声强度=60 dB,3.45±2.99 vs 3.04±2.76,P<0.001)。结论运动状态对纹状体的听觉响应具有显著的抑制作用,这可能是导致运动状态时声音信息的识别能力下降的重要原因。
文摘本刊开办异或新虹栏目,旨在每期介绍一位在海外定居,学有成就的华裔学者,他们将介绍国外最新的临床、科研动态,同时欢迎对国内专业发展提出建设性意见,畅所欲言,批评争鸣,以诚恳求实的治学态度与国内同仁同道共勉。同时借本栏目广招天下饱学贤良之才,热情杂志建设之士,共办《Jounal of Otology》,为促进国际间合作搭建一个学术交流的平台,有效快速地将中国不断发展的耳科学成果向世界展示,欢迎广大海外学者积极投稿。
文摘A sustained monaural block of auditory air-conduction model was established in rats through subcutaneous suture in the right ear canal.The gene expression levels of hypothalamic N-methyl-D-aspartate receptor NR1,NR2A,NR2B and NR2C mRNA in the auditory central nervous system of Sprague-Dawley rats at postnatal 9,23,37 days were determined after an environmental change.Reverse transcription-PCR assay showed that the critical period for the development of NR1,NR2A,and NR2B subunits in the left hypothalamus and NR1-and NR2B-dependent auditory neurons in the right hypothalamus terminated 23 days after the suture in the right ear.The critical period for the development of NR2A subunit-dependent auditory neurons in the right hypothalamus was terminated by postnatal day 37.The results confirmed that N-methyl-D-aspartate receptor subunits in the hypothalamus may be regulated by the auditory environment.
基金supported by the National Natural Science Foundation of China (31171059, 30930039 and 30970982)Program for Changjiang Scholars and Innovative Research Team in University (IRT1142)
文摘In this study, we investigated the features of latency-amplitude (L-A) functions at different sound frequencies, using extracellular recording from auditory neurons in the central nucleus of the inferior colliculus (ICC) in mice. Isofrequency L-A functions from single neurons could be fit with a newly developed equation based on Pieron's law. The high degree of fitness indicates that the curvatures of all isofrequency L-A functions for a given neuron are similar, and that the difference between L-A functions is due to a shift in their positions in the coordinate system. When we normalized the L-A functions to match the position of the L-A function obtained at the neuronal characteristic frequency (CF), all isofrequency L-A functions from a given ICC neuron were highly superimposed. The similar shapes of the L-A functions at different frequencies may reflect the physical laws of sound being transferred into bioelectric signals. The position of a non-CF L-A function could be measured as the differences of the asymptotic L and A ( L and A) compared to the L-A function at a reference frequency such as the CF. The nerve fibers and synapses connecting to a neuron for acoustic information processing can be functionally simplified as a single "wire" (as the total length of nerve fibers) and "joint" (as the summated size/strength of synapses). The wire and joint mediate information transmission and transduction, respectively. Thus, L and A may be measurements of the total length of nerve fibers and the strength of summated synapses in the activated auditory pathway. L and A differed between frequency channels and neurons, suggesting that the differences of acoustic neuronal responses are always caused by activation of different pathways, and that the pathways that process sounds are diverse.
