Department of Biology, 3118 Biosciences Complex, Queen's University, Kingston, ON, Canada, K7L 3N6.
J Exp Biol. 2022 Jun 1;225(11). doi: 10.1242/jeb.244097. Epub 2022 Jun 8.
Rapid cold hardening (RCH) is a type of phenotypic plasticity that delays the occurrence of chill coma in insects. Chill coma is mediated by a spreading depolarization of neurons and glia in the CNS, triggered by a failure of ion homeostasis. We used biochemical and electrophysiological approaches in the locust, Locusta migratoria, to test the hypothesis that the protection afforded by RCH is mediated by activation of the Na+/K+-ATPase (NKA) in neural tissue. RCH did not affect NKA activity measured in a biochemical assay of homogenized thoracic ganglia. However, RCH hyperpolarized the axon of a visual interneuron (DCMD) and increased the amplitude of an activity-dependent hyperpolarization (ADH) shown previously to be blocked by ouabain. RCH also improved performance of the visual circuitry presynaptic to DCMD to minimize habituation and increase excitability. We conclude that RCH enhances in situ NKA activity in the nervous system but also affects other neuronal properties that promote visual processing in locusts.
快速冷驯化（RCH）是一种表型可塑性，可延迟昆虫发生冷昏迷。冷昏迷是由中枢神经系统中神经元和神经胶质的去极化扩散介导的，这是由离子动态平衡失调引发的。我们在蝗虫（Locusta migratoria）中使用生化和电生理方法来检验假设，即 RCH 提供的保护是通过激活神经组织中的 Na+/K+-ATP 酶（NKA）来介导的。RCH 不会影响在胸部神经节匀浆的生化测定中测量的 NKA 活性。然而，RCH 使视觉中间神经元（DCMD）的轴突超极化，并增加了先前被哇巴因阻断的活性依赖性超极化（ADH）的幅度。RCH 还改善了 DCMD 之前的视觉回路的性能，以最小化习惯化并增加兴奋性。我们得出的结论是，RCH 增强了神经系统中 NKA 的原位活性，但也影响了其他促进蝗虫视觉处理的神经元特性。
