发布: 2017年07月05日第7卷第13期 DOI: 10.21769/BioProtoc.2388 浏览次数: 9900
评审: Jihyun KimAdler R. DillmanAnonymous reviewer(s)
Abstract
To investigate cellular, molecular and behavioral mechanisms of noxious cold detection, we developed cold plate behavioral assays and quantitative means for evaluating the predominant noxious cold-evoked contraction behavior. To characterize neural activity in response to noxious cold, we implemented a GCaMP6-based calcium imaging assay enabling in vivo studies of intracellular calcium dynamics in intact Drosophila larvae. We identified Drosophila class III multidendritic (md) sensory neurons as multimodal sensors of innocuous mechanical and noxious cold stimuli and to dissect the mechanistic bases of multimodal sensory processing we developed two independent functional assays. First, we developed an optogenetic dose response assay to assess whether levels of neural activation contributes to the multimodal aspects of cold sensitive sensory neurons. Second, we utilized CaMPARI, a photo-switchable calcium integrator that stably converts fluorescence from green to red in presence of high intracellular calcium and photo-converting light, to assess in vivo functional differences in neural activation levels between innocuous mechanical and noxious cold stimuli. These novel assays enable investigations of behavioral and functional roles of peripheral sensory neurons and multimodal sensory processing in Drosophila larvae.
Keywords: Nociception (伤害感受)Background
The capacity to sense and respond appropriately to environmental cues is one of the most fundamental aspects shared among the metazoans. Sensing potentially harmful stimuli, such as noxious temperature, chemical or mechanical insults, and responding appropriately is crucial for avoiding incipient damage that can lead to injury or death. Typically, upon sensing nociceptive stimuli an animal produces a set of avoidance behaviors that either mitigate or allow the animal to escape the noxious stimulus. Elucidating molecular, cellular, and behavioral level mechanisms in processing nociceptive stimuli is of great interest as there is potential for the identification and development of novel therapeutic interventions for aberrant sensory processing, which can lead to neuropathic pain. Sensory and behavioral responses to noxious chemical, mechanical and heat stimuli have been elucidated in Drosophila melanogaster larvae and adults, however, noxious cold detection has only recently been discovered in larvae (Im and Galko, 2012; Gorczyca et al., 2014; Guo et al., 2014; Mauthner et al., 2014; Turner et al., 2016). Drosophila larvae exhibit a distinct set of aversive behaviors in responses to noxious cold stimuli with the predominant cold-evoked response displaying as a bilateral anterior-posterior full body contraction (CT) (Turner et al., 2016). This behavioral response is mediated by class III md sensory neurons (Turner et al., 2016), which intriguingly have also been implicated in gentle touch mechanosensation revealing multimodality in these neurons (Tsubouchi et al., 2012; Yan et al., 2013). The Transient Receptor Potential (TRP) channels Pkd2, NompC, and Trpm are required for mediating noxious cold-evoked behavior and behavioral selection in response to innocuous mechanical vs. noxious cold stimuli is dependent upon class III neural activation levels providing insight into the mechanisms underlying cold nociception and multimodal sensory processing (Turner et al., 2016).
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版权信息
© 2017 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Patel, A. A. and Cox, D. N. (2017). Behavioral and Functional Assays for Investigating Mechanisms of Noxious Cold Detection and Multimodal Sensory Processing in Drosophila Larvae. Bio-protocol 7(13): e2388. DOI: 10.21769/BioProtoc.2388.
分类
神经科学 > 行为神经科学 > 实验动物模型
细胞生物学 > 细胞成像 > 荧光
细胞生物学 > 细胞成像 > 活细胞成像
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