Robertson R Meldrum, Björnfors E Rebecka, Sillar Keith T
Department of Biology, Queen's University, Kingston, Ontario, Canada.
Neuroreport. 2010 Oct 6;21(14):943-7. doi: 10.1097/WNR.0b013e32833e332d.
We investigated the effects of chemical hypoxia on the central pattern generator controlling swimming in stage 42 Xenopus laevis larvae. We recorded motoneuron activity from ventral roots of immobilized tadpoles and evoked swim episodes by brief electrical stimulation of the tail skin. In the presence of the metabolic inhibitor, sodium azide (5 mM, NaN3), swim episode duration and cycle frequency decreased until swim motor patterns could not be evoked. On recovery, cycle frequency returned to preazide levels; however, episode duration remained short for at least an hour. In addition, recovery induced spontaneous, short bouts of swimming similar to the slow rhythm that is evoked by N-methyl-D-aspartic acid. We conclude that abiotic features of the environment can have long-term modulatory effects on circuit function in the CNS.
我们研究了化学性低氧对处于42期非洲爪蟾幼体中控制游泳的中枢模式发生器的影响。我们从固定化蝌蚪的腹根记录运动神经元活动，并通过短暂电刺激尾部皮肤诱发游泳发作。在存在代谢抑制剂叠氮化钠（5 mM，NaN₃）的情况下，游泳发作持续时间和周期频率降低，直至无法诱发游泳运动模式。恢复时，周期频率恢复到叠氮化钠处理前的水平；然而，发作持续时间至少一小时内仍较短。此外，恢复过程中诱发了自发的、短暂的游泳发作，类似于由N-甲基-D-天冬氨酸诱发的慢节律。我们得出结论，环境的非生物特征可对中枢神经系统中的回路功能产生长期调节作用。
