Gigg J, Tan A M, Finch D M
Brain Research Institute, Reed Neurological Research Center, University of California, Los Angeles 90024-1761.
Cereb Cortex. 1992 Nov-Dec;2(6):477-84. doi: 10.1093/cercor/2.6.477.
Anatomical and physiological studies in the rat have shown projections from the medial dorsal thalamus to the anterior cingulate cortex. We used multibarrel iontophoresis to identify the neurotransmitter used in this thalamic projection. Extracellular responses were recorded from 165 cingulate neurons in anesthetized rats after electrical stimulation of the medial dorsal thalamus and vicinity. Forty-four of these cells (27%) showed an excitatory response to thalamic stimulation. In a further 40 cells that showed no baseline excitation, iontophoresis of the GABAA antagonist bicuculline methiodide revealed excitatory responses. The GABAB antagonist CGP-35348 attenuated longer-latency inhibition in 5 of 10 cells. In 23 of 49 (47%) of the above cells, AMPA antagonist iontophoresis (either CNQX or DNQX) selectively decreased the excitatory response to thalamic stimulation. The NMDA antagonist 3[(R)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid had no such effect. These data suggest that the thalamic projection to anterior cingulate cortex is glutamatergic, acting principally via AMPA receptors, and that the response of cingulate neurons to thalamic stimulation is regulated by GABA acting at both GABAA and GABAB receptors.
对大鼠的解剖学和生理学研究表明，从内侧背侧丘脑到前扣带回皮层存在投射。我们使用多管离子电泳来确定该丘脑投射中所使用的神经递质。在电刺激内侧背侧丘脑及其附近区域后，从麻醉大鼠的165个扣带回神经元记录细胞外反应。其中44个细胞（27%）对丘脑刺激表现出兴奋性反应。在另外40个无基线兴奋的细胞中，GABAA拮抗剂甲磺酸荷包牡丹碱的离子电泳显示出兴奋性反应。GABAB拮抗剂CGP - 35348减弱了10个细胞中5个细胞的长潜伏期抑制。在上述49个细胞中的23个（47%）中，AMPA拮抗剂离子电泳（CNQX或DNQX）选择性地降低了对丘脑刺激的兴奋性反应。NMDA拮抗剂3 - [(R)-2 - 羧基哌嗪 - 4 - 基]-丙基 - 1 - 膦酸没有这种作用。这些数据表明，丘脑到前扣带回皮层的投射是谷氨酸能的，主要通过AMPA受体起作用，并且扣带回神经元对丘脑刺激的反应受作用于GABAA和GABAB受体的GABA调节。
