青年猫与老年猫初级听皮层GABA_A受体免疫表达的比较研究

目的对5只老年猫(12岁,3-3.5kg)与5只青年猫(2岁,3-3.5kg)初级听皮层(AI)γ-氨基丁酸(gamma-aminobutyric acid,GABA)A受体神经元进行免疫表达比较研究,探索老年猫与青年猫初级听皮层(AI)GABAA受体年龄性变化及产生可影响的生理作用。方法运用免疫组织化学反应与免疫印迹相结合的方法对不同年龄组动物(AI)组织进行染色。光学显微镜下观察、拍照;免疫组织化学阳性反应示GABAA R-IR(GABAA receptor-immunoreaction)神经元形态、密度及分布;免疫印迹示GABAA受体蛋白含量变化。结果老年猫的AI区GABAA R-IR神经元密度比青年猫的GABAA R-IR下降了29.19%,阳性反应强度减弱了20.7%,老年猫阳性反应细胞占神经元总数百分比比青年猫的减少了5.32%;老年猫的GABAA受体蛋白表达量比青年猫的下降了23.16%。结论初级听皮层GABAA受体细胞及受体表达下调可能是老年个体听觉功能减退的重要原因。

A comparative study of GABAA receptor expression in the primary auditory cortex of young and old cats

Objective Immunological study was implemented on GABAA receptor neurons in the pri-mary auditory cortex fAD of 5 young cats （2 years old, 3 3.5kg） and 5 old cats （12 years old, 3 3.5kg）, in order to explore the age related changes. Methods The same regions of AI were comparatively studied. Immunohistochemical staining and western blot were used to explore the differences of GABAA receptor cells in AI between young and old cats. Serial sections and tissue from the two age groups were stained in anti GABAA receptor immunoreactivity for localizing and characterizing GABAA receptor neurons, and Western blot with anti GABAA receptor showed that the expressed product was designed GABAA receptor protein in AI. Results Compared with those of the young cats, the density of GABAA receptor neurons in AI of old cats was 29. 19% lower, positive reaction intensity decreases 20. 7%, immunoreactive positive cell percentage of the total number of neurons was down more than 5.32%, and GABAA receptor protein expression fell by 23. 16%. Conclusion The results provide a direct morphologic evidence for the decline of GABAA receptors in the primary auditory cortex, which is considered to a possible reason for the age relat ed decline in auditory capabilities.