de Curtis M, Spreafico R, Avanzini G
Department of Neurophysiology, Istituto Neurologico Carlo Besta, Milan, Italy.
Neuroscience. 1989;33(2):275-83. doi: 10.1016/0306-4522(89)90207-8.
The effects of the excitatory amino acids on the nucleus reticularis thalami were examined by intracellular recordings from rat thalamic slices. Non-N-methyl-D-aspartate receptor agonists and glutamate induced a membrane depolarization and a reduction in input resistance, while N-methyl-D-aspartate and aspartate induced a prolonged discharge, which in some neurons took the form of a burst firing associated with an apparent increase in membrane input resistance. Both the N-methyl-D-aspartate and the aspartate effects were blocked by D-2-amino-5-phosphonovalerate, while the effects of glutamate, kainate and quisqualate were not. The excitatory postsynaptic potential evoked by corticothalamic fiber stimulation shows two components: an early, short-lasting, 2-amino-5-phosphonovalerate-insensitive portion, and a late, 2-amino-5-phosphonovalerate-sensitive decay phase. It is suggested that glutamate acts in nucleus reticularis thalami cells preferentially on the non-N-methyl-D-aspartate receptors, while aspartate shows an N-methyl-D-aspartate-like effect. The two excitatory amino acids glutamate and aspartate play a determinant role in the modulation of thalamic activity driven by corticothalamic projection.
通过对大鼠丘脑切片进行细胞内记录，研究了兴奋性氨基酸对丘脑网状核的影响。非N-甲基-D-天冬氨酸受体激动剂和谷氨酸可引起膜去极化和输入电阻降低，而N-甲基-D-天冬氨酸和天冬氨酸可引起长时间放电，在某些神经元中表现为爆发式放电，伴有膜输入电阻明显增加。N-甲基-D-天冬氨酸和天冬氨酸的作用均被D-2-氨基-5-膦酰基戊酸阻断，而谷氨酸、海人藻酸和quisqualate的作用则未被阻断。皮质丘脑纤维刺激诱发的兴奋性突触后电位显示出两个成分：一个早期、短暂的、对2-氨基-5-膦酰基戊酸不敏感的部分，以及一个晚期、对2-氨基-5-膦酰基戊酸敏感的衰减期。提示谷氨酸在丘脑网状核细胞中优先作用于非N-甲基-D-天冬氨酸受体，而天冬氨酸表现出类似N-甲基-D-天冬氨酸的作用。谷氨酸和天冬氨酸这两种兴奋性氨基酸在由皮质丘脑投射驱动的丘脑活动调节中起决定性作用。
