Skoog B, Noga B R
Department of Physiology and Pharmacology, Göteborg University, Sweden.
Exp Brain Res. 1995;105(1):39-47. doi: 10.1007/BF00242180.
The effects of dopamine and its agonists on transmission from muscle afferents to spinal neurones were investigated in the cat and guinea-pig spinal cord, by measuring the drug effects on the amplitude of monosynaptic field potentials evoked by electrical stimulation of group I and group II muscle afferents. Local iontophoretic application of dopamine, the dopamine D1/D5 agonist SKF-38393 and the D2/D3/D4 agonist quinpirole all depressed the group II field potentials evoked at the base of the dorsal horn. Group II field potentials in the intermediate zone were depressed by dopamine to a similar degree as the dorsal horn field potentials, whereas the dopamine agonists were without effect upon them. The intermediate zone field potentials evoked by group I muscle afferents were not depressed by any of the drugs. The dopamine-evoked depression of the group II-evoked field potentials in the dorsal horn in the guinea-pig spinal cord was reduced by the simultaneous application of haloperidol. The results demonstrate that dopamine receptors mediate the depression of transmission from group II muscle afferents to interneurones in the dorsal horn, but not to neurones in the intermediate zone of the spinal cord.
通过测量多巴胺及其激动剂对电刺激 I 类和 II 类肌肉传入纤维诱发的单突触场电位幅度的影响，在猫和豚鼠脊髓中研究了多巴胺及其激动剂对从肌肉传入纤维到脊髓神经元传递的作用。多巴胺、多巴胺 D1/D5 激动剂 SKF - 38393 和 D2/D3/D4 激动剂喹吡罗的局部离子电渗应用均抑制了在背角底部诱发的 II 类场电位。中间带的 II 类场电位被多巴胺抑制的程度与背角场电位相似，而多巴胺激动剂对其无作用。I 类肌肉传入纤维诱发的中间带场电位不受任何一种药物的抑制。在豚鼠脊髓中，同时应用氟哌啶醇可减轻多巴胺诱发的背角 II 类诱发场电位的抑制。结果表明，多巴胺受体介导了从 II 类肌肉传入纤维到背角中间神经元的传递抑制，但不介导到脊髓中间带神经元的传递抑制。
