Excitatory and inhibitory neurotransmitters in the nucleus rotundus of pigeons
Excitatory and inhibitory neurotransmitters in the nucleus rotundus of pigeons
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鸽子圆核中的兴奋性和抑制性神经递质
DOI：
10.1017/s095252380000938x
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发表时间：
1995
影响因子：
1.9
通讯作者：
S. Wang
中科院分区：
文献类型：
--
作者：
H. F. Gao;G. Y. Wu;B. Frost;S. Wang
本文观察了谷氨酸及其激动剂NMDA和AMPA，拮抗剂CPP和CNQX，以及GABA及其拮抗剂荷包牡丹碱对鸽(Columba Livia)旋转神经元视觉和顶盖刺激诱发反应的影响。离子导入谷氨酸可兴奋全部48个肾小管上皮细胞，其中98%的细胞可被CNQX阻断，而CPP不能阻断，2%的细胞可被CNQX或CPP阻断。在AMPA兴奋的21个细胞中，有20个细胞也被NMDA兴奋，这表明AMPA和NMDA受体可能在大多数圆形细胞中共存。电刺激顶盖可在另外36个细胞中诱发出动作电位，CNQX也能阻断这些动作电位，但CPP不能。另外8个亮度单位和21个运动敏感单位记录的视觉反应也被CNQX而不是CPP阻断。另一方面，GABA抑制视觉反应和顶盖刺激引起的反应。荷包牡丹碱可消除顶盖刺激后的抑制期。综上所述，这些结果表明，谷氨酸可能是一种兴奋性递质，主要通过非NMDA受体(AMPA受体)在顶盖-丘脑传递中发挥作用。同时，GABA可能是鸽圆核内的抑制性递质。
Abstract Rotundal neurons in pigeons (Columba livia) were examined for the effects of glutamate and its agonists NMDA and AMPA, antagonists CPP and CNQX, as well as of GABA and its antagonist bicuculline, on visual and tectal stimulation-evoked responses. Glutamate applied by iontophoresis excited all 48 rotundal cells tested, and this excitation was blocked by CNQX but not by CPP in 98% of cases, with 2% of cells being blocked by either CNQX or CPP. Out of 21 cells excited by AMPA, 20 were also excited by NMDA, indicating that AMPA and NMDA receptors may coexist in most rotundal cells. Action potentials were evoked in 36 additional cells by electrical stimulation applied to the tectum and they were also blocked by CNQX but not CPP. Visual responses recorded from a further eight luminance units and 21 motion-sensitive units were also blocked by CNQX and not CPP. On the other hand, GABA inhibited visual responses as well as responses evoked by tectal stimulation. An inhibitory period following tectal stimulation was eliminated by bicuculline. Taken together, these results indicate that glutamate may be an excitatory transmitter acting predominantly through non-NMDA receptors (AMPA receptors) in tectorotundal transmission. Meanwhile, GABA may be an inhibitory transmitter in the pigeon nucleus rotundus.