Prakash Brooke A, Toro Cecilia Phillips
Biology Department, Sarah Lawrence College, Bronxville, NY 10708.
J Undergrad Neurosci Educ. 2019 Dec 21;18(1):A57-A64. eCollection 2019 Fall.
Zebrafish detect the light levels of their surroundings and adjust their coloration in response. By controlling the location of melanosome pigment granules within melanocytes in their dermis, fish can lighten or darken their appearance to blend in with their environment. This camouflage response pathway, which begins in the retina and ends in the melanocyte, involves both neuronal and endocrine signaling. Ultimately, two hormones, α-melanocyte stimulating hormone and melanin concentrating hormone, converge on the melanocyte and cause dispersion or aggregation of melanosomes, respectively; the camouflage behavior can therefore be modulated both environmentally and pharmacologically. Here, we describe a two-part protocol designed for use in an undergraduate laboratory. Students induce the camouflage response by exposing zebrafish larvae to darkness or bright light, in conjunction with pharmacological treatments that alter the ability of the larvae to properly respond to these environmental cues. Students then fix the larvae, take photographs of their samples using their smartphones and dissecting microscopes, and directly measure the camouflage response by quantifying the size of melanocytes using ImageJ software. Finally, students present their data in a single professional-quality figure with an accompanying detailed figure legend. This protocol enables students to gain unique laboratory experiences in which they modulate and quantify a hormone-driven behavior, observable on a cellular level. It can therefore complement course topics in neurobiology, endocrinology, animal physiology, animal behavior, and cell biology classes.
斑马鱼能检测周围环境的光照水平并做出相应的体色调整。通过控制真皮层黑素细胞内黑素体色素颗粒的位置，斑马鱼可以使自己的外观变亮或变暗，以融入周围环境。这种伪装反应途径始于视网膜，止于黑素细胞，涉及神经和内分泌信号传导。最终，两种激素，即α-黑素细胞刺激素和黑素浓集激素，作用于黑素细胞，分别导致黑素体的分散或聚集；因此，伪装行为可以通过环境因素和药物进行调节。在这里，我们描述了一个分为两部分的实验方案，供本科实验室使用。学生通过将斑马鱼幼虫置于黑暗或强光环境中，并结合改变幼虫对这些环境线索做出正确反应能力的药物处理，来诱导伪装反应。然后，学生固定幼虫，使用智能手机和解剖显微镜拍摄样本照片，并通过使用ImageJ软件量化黑素细胞的大小来直接测量伪装反应。最后，学生将他们的数据呈现为一个具有专业水准的单一图表，并附上详细的图表说明。该实验方案使学生能够获得独特的实验室体验，在其中他们调节和量化一种激素驱动的行为，这种行为在细胞水平上是可观察到 的。因此，它可以补充神经生物学、内分泌学、动物生理学、动物行为学和细胞生物学课程的主题。
