School of Psychology and Neuroscience, the University of St Andrews, St Mary's Quad,South Street, St Andrews, Fife, KY16 9JP, UK.
School of Psychology and Neuroscience, the University of St Andrews, St Mary's Quad,South Street, St Andrews, Fife, KY16 9JP, UK.
Brain Res Bull. 2018 May;139:278-284. doi: 10.1016/j.brainresbull.2018.03.015. Epub 2018 Mar 27.
Muscarinic acetylcholine receptors (mAChRs) mediate effects of acetylcholine (ACh) in many systems, including those involved in spinal functions like locomotion. In Xenopus laevis tadpoles at two days old, a model vertebrate for motor control research, we investigated the role of mAChRs in the skin mechanosensory pathway. We found that mAChR activation by carbachol did not affect the sensory Rohon-Beard neuron properties. However, carbachol could hyperpolarise sensory interneurons and decrease their voltage responses to outward currents. Carbachol could increase the threshold for the mechanosensory pathway to start swimming, preventing the initiation of swimming at higher concentrations altogether. Recording from the sensory interneurons in carbachol showed that their spiking after skin stimulation was depressed. However, the general muscarinic antagonist atropine did not have a clear effect on the swimming threshold or the modulation of sensory interneuron membrane conductance. Our results suggest the skin mechanosensory pathway may be subject to muscarinic modulation in this simple vertebrate system.
毒蕈碱型乙酰胆碱受体 (mAChR) 在许多系统中介导乙酰胆碱 (ACh) 的作用，包括参与运动等脊髓功能的系统。在两天大的非洲爪蟾蝌蚪中，一种用于运动控制研究的典型脊椎动物模型，我们研究了 mAChR 在皮肤机械感觉通路中的作用。我们发现，毒蕈碱乙酰胆碱激动剂卡巴胆碱激活 mAChR 不会影响感觉罗氏神经节神经元的特性。然而，卡巴胆碱可以使感觉中间神经元超极化，并降低它们对外流电流的电压反应。卡巴胆碱可以增加机械感觉通路开始游泳的阈值，完全阻止在更高浓度下开始游泳。在卡巴胆碱中记录感觉中间神经元的活动表明，它们在皮肤刺激后的放电被抑制。然而，一般的毒蕈碱拮抗剂阿托品对游泳阈值或感觉中间神经元膜电导的调制没有明显的影响。我们的结果表明，在这个简单的脊椎动物系统中，皮肤机械感觉通路可能受到毒蕈碱的调制。
