Functional Assessment of Melanopsin-Driven Light Responses in the Mouse: Multielectrode Array Recordings
Intrinsically photosensitive retinal ganglion cells (ipRGCs) are a special subset of retinal output neurons capable of detecting and responding to light via a unique photopigment called melanopsin. Melanopsin activation is essential to a wide array of physiological functions, especially to those related to non-image-forming vision. Since ipRGCs only constitute a very small proportion of retinal ganglion cells, targeted recording of melanopsin-driven responses used to be a big challenge to vision researchers. Multielectrode array (MEA) recording provides a noninvasive, high throughput method to monitor melanopsin-driven responses. When synaptic inputs from rod/cone photoreceptors are silenced with glutamatergic blockers, extracellular electric signals derived from melanopsin activation can be recorded from multiple ipRGCs simultaneously by tens of microelectrodes aligned in an array. In this chapter we describe how our labs have approached MEA recording of melanopsin-driven light responses in adult mouse retinas. Instruments, tools and chemical reagents routinely used for setting up a successful MEA recording are listed, and a standard experimental procedure is provided. The implementation of this technique offers a useful paradigm that can be used to conduct functional assessments of ipRGCs and NIF vision.
Key wordsIntrinsically photosensitive retinal ganglion cells Melanopsin Multielectrode array Mouse Retina
The research of the authors is supported by grants from the National Natural Science Foundation of China (31571072, 31100796, 31571075, 31171005, 31421091, 81790640 and 81430007); the Ministry of Science and Technology of China (2011CB504602 and 2015AA020512); NIH R15 EY026255 and the Karl Kirchgessner Foundation.