Eriksson J, Olausson B, Jankowska E
Department of Clinical Neuroscience, Göteborg University, Sweden.
Exp Brain Res. 1996 Sep;111(2):296-304. doi: 10.1007/BF00227307.
Antispastic effects of the noradrenaline and dopamine precursor l-3,4-dihydroxyphelanine (L-dopa) were investigated in 11 subjects in which exaggerated stretch reflexes developed after spinal cord injuries. The effects were evaluated from changes in the electromyographic (EMG) response of the quadriceps muscle during tendon jerks evoked by standardized taps over the patellar tendon, in clonus and in resistance to passive movements of the limb. After administration of L-dopa, EMG responses occurring 30-150 ms after the tendon tap decreased to about 50% of control, and clinical tests revealed a marked decrease in the resistance to muscle stretches and in the degree of clonus. The effects were maximal within about 1 h. The depressive actions of L-dopa are interpreted as being exerted primarily at the spinal level, since they were evoked in paraplegics and tetraplegics. The results support the previous hypothesis that group II muscle afferents contribute to.the exaggerated stretch reflex in spastic patients because L-dopa depresses transmission from group II but not from group I muscle afferents. They also indicate the possibility of using L-dopa in the treatment of spastic patients.
在11名脊髓损伤后出现夸张牵张反射的受试者中，研究了去甲肾上腺素和多巴胺前体L-3,4-二羟基苯丙氨酸（L-多巴）的抗痉挛作用。通过标准化轻敲髌腱诱发的腱反射、阵挛以及肢体被动运动阻力过程中股四头肌的肌电图（EMG）反应变化来评估其效果。给予L-多巴后，腱反射轻敲后30 - 150毫秒出现的EMG反应降至对照值的约50%，临床测试显示肌肉拉伸阻力和阵挛程度显著降低。效果在约1小时内达到最大。L-多巴的抑制作用主要被解释为在脊髓水平发挥作用，因为它们在截瘫和四肢瘫患者中诱发。这些结果支持了先前的假设，即II类肌肉传入神经促成了痉挛患者夸张的牵张反射，因为L-多巴抑制来自II类而非I类肌肉传入神经的传递。它们还表明了使用L-多巴治疗痉挛患者的可能性。
