Emanuel Stav, Libersat Frederic
Department of Life Sciences and Zlotowski Center for Neurosciences, Ben Gurion University, Beer Sheva, Israel.
Front Physiol. 2019 Aug 21;10:1100. doi: 10.3389/fphys.2019.01100. eCollection 2019.
Detecting and avoiding environmental threats such as those with a potential for injury is of crucial importance for an animal's survival. In this work, we examine the nociceptive pathway in an insect, the cockroach , from detection of noxious stimuli to nocifensive behavior. We show that noxious stimuli applied to the cuticle of cockroaches evoke responses in sensory axons that are distinct from tactile sensory axons in the sensory afferent nerve. We also reveal differences in the evoked response of post-synaptic projection interneurons in the nerve cord to tactile versus noxious stimuli. Noxious stimuli are encoded in the cockroach nerve cord by fibers of diameter different from that of tactile and wind sensitive fibers with a slower conduction velocity of 2-3 m/s. Furthermore, recording from the neck-connectives show that the nociceptive information reaches the head ganglia. Removing the head ganglia results in a drastic decrease in the nocifensive response indicating that the head ganglia and the nerve cord are both involved in processing noxious stimuli.
检测并躲避诸如那些具有潜在伤害性的环境威胁对动物的生存至关重要。在这项研究中，我们研究了一种昆虫——蟑螂的伤害感受通路，从有害刺激的检测到伤害防御行为。我们发现，施加于蟑螂表皮的有害刺激会在感觉轴突中引发反应，这些反应与感觉传入神经中的触觉感觉轴突不同。我们还揭示了神经索中突触后投射中间神经元对触觉刺激与有害刺激的诱发反应存在差异。在蟑螂的神经索中，有害刺激由直径不同于触觉和风速敏感纤维的纤维进行编码，其传导速度较慢，为2 - 3米/秒。此外，从颈部连接体记录的数据表明，伤害感受信息会到达头部神经节。去除头部神经节会导致伤害防御反应急剧下降，这表明头部神经节和神经索都参与了有害刺激的处理过程。
