【作者】 储昭灿；

【导师】 李金钢；

【作者基本信息】 陕西师范大学 ， 动物学， 2007， 硕士

【摘要】 地下鼠是高度特化的哺乳动物，在感觉系统上出现一系列变化以适应地下生活环境，在长期的地下适应过程中，地下鼠类在听觉方面出现明显的适应性进化，总体上来看，其听觉敏感频率偏于低频，与声波在地下洞道中的传播能力相一致。地下鼠低频适听研究的核心同样在于对其耳蜗活动机制的理解。本研究用组织学，电生理学方法，对甘肃鼢鼠(Myospalax cansus)耳蜗组织结构、听觉毛细胞扫描观察及其听神经电生理作了研究，结果表明：甘肃鼢鼠耳蜗结构和其它哺乳类动物耳蜗结构相似，具有典型的螺旋形构造，共有3.5圈，螺旋神经节清晰可见，且分为大而染色深、小而染色浅的两种类型，从蜗底到蜗顶，螺旋神经节的数目逐渐增多。甘肃鼢鼠耳蜗中，各圈中内毛细胞均为一排，其上听纤毛线形排列，大约30根。外毛细胞3排，其上听纤毛4排，每排大约30根，每束大约120根左右，呈弧形排列，没有明显的“W”排列方式，而主要呈半圆形，听纤毛由内向外逐渐增高，排列整齐，形态完整。毛细胞间隙较小，内毛细胞顶端听纤毛较外毛细胞顶端听纤毛长。OHC之间间隙较小，同一排之内的毛细胞间距很小，各排OHC之间镶嵌排列，各细胞之间几乎粘连。听性脑干反应测定click短声检测结果表明，雌性最低听阈声压水平只能达到35±0.50dB SPL，雄性个体为40±0.01dB SPL，相同条件下根田鼠(Microtus oeconomus)最低听阈声压水平达到21±0.67dB SPL。各单音频率刺激数据结果显示，甘肃鼢鼠最佳听力在12kHz左右，雌性听阈声压水平为37±0.50dB，雄性听阈略高，为40±0.83dB SPL，根田鼠最佳听力在24 kHz左右，最低听阈为19±0.17 dB。低于1kHz和高于16kHz，甘肃鼢鼠听阈声压水平均超过60dB SPL，说明甘肃鼢鼠听觉敏感偏于中低频。更多还原

【Abstract】 Subterranean rodents show a series of changes in sense organs to adapt theunderground environment, for example, olfaction highly evolved, be sensitive to touch,and bones structure of forelimbs obviously changed in order to dig holes efficiently.In order to find the evidence of Myospalax cansus’ adaptation to low frequencysound waves, three groups experiments about the hearing ability of Myospalax cansushave finished, which are histological research, sanning electron mieoscope research aboutMyospalax cansus’ cochlea, and the measure of auditory brainstem response aboutMyospalax cansus.The results show that the cochlea structures between Myospalax cansus and othermammals are similar, it also have a typical screwy structure, and it have three point fivecircles aggregately. The helix ganglions are clear, which include big deeply dyed cellsand small shallowly dyed cells, from the bottom to the top of the cochlea, the number ofthe helix ganglions gradually increases.Tissue treated with scanning electron microscopy, in Myospalax cansus’ cochlea,the inner hair cells are arranged in a line, and there are about thirty stereocilia on the topof inner hair cells, they are arranged in linear. Outer hair cells are arranged in three rows,there are about four rows stereocilia on every outer hair cell, and there are about thirtystereocilia every row, about one hundred and twenty stereocilia every bundle, they arearranged like a "C" do not present typical "W" shape. These stereocilia arranged orderly,and the length of the stereocilia heightened from inside to outer side of the stereociliabundle gradually. The space between outer hair cells is small, and outer hair cells indifferent rows arranged inlaid.During auditory brainstem response process, the result of click stimulate show thatthe lowest auditory threshold of female Myospalax cansus only reach 35±5dB SPL, andthe male 40±5dB SPL, under the same condition, the lowest auditory threshold ofMicrotus oeconomus can reach 21±0.67dB SPL. Results of single frequencies stimulateshow that the best sound waves for Myospalax cansus are around 12 kHz, the lowest auditory threshold of female Myospalax cansus reach 37±0.5dB SPL, and the male40±0.0dB SPL, the best sound waves for Microtus oeconomus are around 24kHz, thelowest auditory threshold of Microtus oeconomus reach 19±0.17 dB SPL.Waves below 1 kHz or higher than 16 kHz, the auditory threshold of Myospalaxcansus overrun 60dB SPL, which show that the auditory sensitive waves of Myospalaxcansus focus on medial and low frequencies.更多还原