Sáez J A, Palomares J M, Vives F, Domínguez I, Villegas I, Montes R, Price D J, Ferrer J M
Departamento de Neurofisiología Clínica, Hospital Virgen de las Nieves, Granada, Spain.
Eur J Neurosci. 1998 Sep;10(9):2790-801. doi: 10.1111/j.1460-9568.1998.00289.x.
The projection from the dorsal lateral geniculate nucleus to the primary visual cortex of the rat was studied electrophysiologically. Electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract produced three types of responses on neurons of area 17: excitation followed by inhibition, excitation and inhibition. These results extend and confirm, in adult rats, previous studies done in rat geniculate-visual cortex cocultures preparations in vitro. The role of glutamate in the neurotransmission of the rat geniculo-cortical pathway was also investigated. In a first set of experiments, the effects of kynurenate, an antagonist of glutamate receptors, on visual cortex neurons with a monosynaptic excitatory response to dorsal lateral geniculate nucleus stimulation were studied. Microiontophoresis of kynurenate in area 17 neurons selectively suppressed the excitatory response to dorsal lateral geniculate nucleus and optic tract stimulation. In a second set of experiments, the effects of electrical stimulation of the dorsal lateral geniculate nucleus and the optic tract on the release of amino acids in the rat visual cortex in vivo were studied. Using the push-pull method, we perfused a discrete region of the visual cortex with artificial cerebrospinal fluid (CSF), and the amino acid content of the perfusates was analysed by high performance liquid chromatography (HPLC). Stimulation of either the dorsal lateral geniculate nucleus or the optic tract significantly increased glutamate release in area 17. The rest of the amino acids studied did not show significant changes. The results provide evidence for the participation of glutamate in the neurotransmission of the geniculo-cortical pathway in the rat.
用电生理学方法研究了大鼠背外侧膝状体核向初级视皮层的投射。对背外侧膝状体核和视束进行电刺激，在17区的神经元上产生了三种类型的反应：兴奋后抑制、兴奋和抑制。这些结果扩展并证实了在成年大鼠中，之前在体外大鼠膝状体 - 视皮层共培养制剂中所做的研究。还研究了谷氨酸在大鼠膝状体 - 皮层通路神经传递中的作用。在第一组实验中，研究了谷氨酸受体拮抗剂犬尿烯酸对背外侧膝状体核刺激有单突触兴奋反应的视皮层神经元的影响。在17区神经元中微量离子导入犬尿烯酸可选择性地抑制对背外侧膝状体核和视束刺激的兴奋反应。在第二组实验中，研究了背外侧膝状体核和视束的电刺激对大鼠视觉皮层体内氨基酸释放的影响。采用推挽法，用人工脑脊液（CSF）灌注视皮层的一个离散区域，并通过高效液相色谱（HPLC）分析灌注液中的氨基酸含量。刺激背外侧膝状体核或视束均显著增加了17区谷氨酸的释放。所研究的其他氨基酸未显示出显著变化。这些结果为谷氨酸参与大鼠膝状体 - 皮层通路的神经传递提供了证据。
