Pirri Jennifer K, McPherson Adam D, Donnelly Jamie L, Francis Michael M, Alkema Mark J
Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Neuron. 2009 May 28;62(4):526-38. doi: 10.1016/j.neuron.2009.04.013.
A key feature of escape responses is the fast translation of sensory information into a coordinated motor output. In C. elegans, anterior touch initiates a backward escape response in which lateral head movements are suppressed. Here, we show that tyramine inhibits head movements and forward locomotion through the activation of a tyramine-gated chloride channel, LGC-55. lgc-55 mutant animals have defects in reversal behavior and fail to suppress head oscillations in response to anterior touch. lgc-55 is expressed in neurons and muscle cells that receive direct synaptic inputs from tyraminergic motor neurons. Therefore, tyramine can act as a classical inhibitory neurotransmitter. Activation of LGC-55 by tyramine coordinates the output of two distinct motor programs, locomotion and head movements that are critical for a C. elegans escape response.
逃避反应的一个关键特征是将感官信息快速转化为协调的运动输出。在秀丽隐杆线虫中，前部触碰会引发向后的逃避反应，在此过程中头部的侧向运动受到抑制。在这里，我们表明酪胺通过激活酪胺门控氯离子通道LGC-55来抑制头部运动和向前运动。lgc-55突变动物在反转行为上存在缺陷，并且在受到前部触碰时无法抑制头部摆动。lgc-55在接受来自酪胺能运动神经元直接突触输入的神经元和肌肉细胞中表达。因此，酪胺可以作为一种经典的抑制性神经递质。酪胺对LGC-55的激活协调了两个不同运动程序的输出，即对秀丽隐杆线虫逃避反应至关重要的运动和头部运动。
