Real‐Time Neurochemical Sensing in Zebrafish: Electrochemical and Fluorescent Approaches

Although originally used to study development, zebrafish ( Danio rerio ) have emerged as a model used to investigate neuronal function in health and disease. Zebrafish are advantageous for this purpose because they are easy to genetically manipulate, are economical to maintain, and share many evolutionarily conserved similarities with the mammalian central nervous systems. Importantly, ex vivo and in vivo preparations are amenable to analytical measurements that employ electrochemical and optical methods to measure fluctuations in neurotransmitter levels. In this review, we take a deeper look into how the inherent advantages of this model organism have been leveraged to unravel fundamental processes involved in neuronal function. To provide proper background and context, we first describe details on how zebrafish became a model for the study of development. We then provide an overview of zebrafish neuroanatomy, highlighting comparisons to mammals. Next, we discuss analytical methods that have been used to measure neurotransmitter and neuromodulatory levels in zebrafish. Finally, we examine specific applications of these methods used to measure real‐time changes in neurochemical levels. This review focuses on electrochemical and fluorescent sensing approaches for monitoring neurochemicals in viable zebrafish preparations, rather than providing a comprehensive examination of extracted‐tissue assays or clinical molecular imaging methods.