GABA能抑制调制大棕蝠下丘听神经元时间编码模式  

THE EFFECTS OF GABA ON TEMPORAL DISCHARGE PATTERNS OF IC NEURONS TO ACOUSTIC PULSR TRAIN IN THE BIG BROWN BAT,Eptesicus fuscus

作　　者：栾瑞红[1] P.H.S.JEN 孙心德[1] 

机构地区：[1]华东师范大学生命科学学院脑科学研究中心,上海200062

出　　处：《生物物理学报》2002年第4期399-403,共5页Acta Biophysica Sinica

基　　金：国家自然科学基金项目(30170313);博士点基金项目(2000026905);上海市重点学科项目;美国国家自然科学基金项目(NSF IBN 9907610)

摘　　要：大棕蝠(Eptesicusfuscus)下丘神经元对重复率为10 pps(pulse per second)、30 pps的串声刺激均产生跟随反应,但对90 pps串声刺激的跟随反应则不尽相同。微电泳bicuculline阻断GABA能抑制作用后,所记录的58个神经元中,有13个(22%)放电率及串声刺激反应模式无变化;45个(78%)神经元放电率有不同程度的增加,对10 pps、30 pps串声刺激仍能产生跟随反应,但对90 pps串声刺激的跟随反应模式有多种变化。其中: 17个(29%)神经元为放电率增加的跟随反应;9个(15%)神经元放电率增加,对前100 ms的串刺激产生反应且放电密集,而对随后200 ms的串刺激只产生少量的放电;15个(26%)神经元放电率增加,在前几十毫秒范围内有较多的放电反应,后续的反应很弱;4个(7%)神经元只对第一个声刺激产生反应,且放电率增加,随后放电急剧减少。结果提示中脑下丘神经元对听觉信息的时间编码可能具有更复杂的机理。In the big brown bat, Eptesicus fuscus, which can use echolocation for hunting and navi-gation, the inferior collicular (IC) neurons responded to every pulse of pulsatile amplitude-modulated (PAM) sound signal train in 10 pps (pulse per second) and 30 pps. But the temporal discharge patterns of IC neurons vary in response to the pulses of 90 pps sound train . The responses of 45(78%) IC neu-rons tested were changed during the application of bicuculline, a competitive antagonist for -aminobu-tyric acid-A (GABA A ) receptors. These neurons responded to every pulse of 10 pps and 30 pps sound train before and during bicuculline application. But when the pulse repetition rate of sound train was 90 pps, the responses of the neurons changed a lot. During bicuculline application, the discharges in-creased and the neurons still responded to every pulse of 90 pps sound train in 17(29%) IC neurons. The responses of 9(15%) neurons increased only at the beginning of 100 ms and decreased greatly in the next 200 ms. In 15(26%) of IC neurons, when the pulses repetition rate was 90 pps, the responses in-creased only in the first several 10 ms and then reduced. There are 4(7%) neurons responding strongly only to the first pulse of 90 pps sound train. The present study suggests that the mechanism of IC pro-cessing temporal information of the sound repetition rate may be more complicated than that of the low-er central auditory system.

关 键 词：GABA GABAA受体 串刺激重复率 回声定位 

分 类 号：Q424[生物学—神经生物学]