Pape H C, Eysel U T
Institut für Physiologie, Universitätsklinikum Essen, F.R.G.
Brain Res. 1988 Feb 2;440(1):79-86. doi: 10.1016/0006-8993(88)91160-2.
Neuronal responses to microiontophoretically applied pulses of acetylcholine (ACh) were recorded in the perigeniculate nucleus (PGN) and dorsal lateral geniculate nucleus (dLGN) of the cat. In the PGN, ACh inhibited 95% of the cells under N2O/O2-halothane anesthesia. Systemic application of sodium pentobarbitone did not abolish ACh inhibition. In the dLGN with N2O-halothane, ACh increased firing rates of neurons before (88%) and after (78%) interruption of their direct retinal inputs by photocoagulation of the receptive field area on the retina. Functional inactivation of the corticogeniculate loop by cooling of the ipsilateral visual cortex did not selectively influence ACh sensitivity in the retinally deafferented dLGN. It is concluded that ACh exerts a direct, excitatory action on geniculate neurons. Infusion of sodium pentobarbitone resulted in reduction of ACh firing rates to about 30% of the control values in 35% of the normally innervated cells (65% of that sample not being excited by ACh), whereas excitatory ACh responses after retinal deafferentation were completely blocked by the barbiturate. It is concluded that pentobarbitone influences direct ACh excitation, but not cholinergic disinhibition in the dLGN or ACh inhibition in the PGN. Possible differential effects of pentobarbitone on nicotinic and muscarinic types of ACh responses are discussed.
在猫的外侧膝状体旁核（PGN）和背外侧膝状体核（dLGN）中记录了神经元对微量离子电泳施加的乙酰胆碱（ACh）脉冲的反应。在PGN中，在N2O/氧气-氟烷麻醉下，ACh抑制了95%的细胞。全身应用戊巴比妥钠并未消除ACh的抑制作用。在使用N2O-氟烷麻醉的dLGN中，在通过光凝视网膜上的感受野区域中断其直接视网膜输入之前（88%）和之后（78%），ACh增加了神经元的放电率。通过冷却同侧视觉皮层使皮质膝状体环路功能失活，并未选择性地影响视网膜去传入的dLGN中ACh的敏感性。得出的结论是，ACh对膝状体神经元发挥直接的兴奋作用。输注戊巴比妥钠导致35%的正常支配细胞中ACh放电率降低至对照值的约30%（该样本的65%未被ACh兴奋），而视网膜去传入后的兴奋性ACh反应被巴比妥酸盐完全阻断。得出的结论是，戊巴比妥钠影响dLGN中ACh的直接兴奋，但不影响其胆碱能去抑制或PGN中ACh的抑制。讨论了戊巴比妥钠对烟碱型和毒蕈碱型ACh反应可能的差异作用。
