Optogenetic manipulation of neuronal and cardiomyocyte functions in zebrafish using microbial rhodopsins and adenylyl cyclases.

Even though microbial photosensitive proteins have been used for optogenetics, their use should be optimized to precisely control cell and tissue functions in vivo. We exploited CCR4 and ChR, cation channelrhodopsins from algae, GC1, a guanylyl cyclase rhodopsin from a fungus, and photoactivated adenylyl cyclases (PACs) from cyanobacteria (PAC) or bacteria (PAC), to control cell functions in zebrafish. Optical activation of CCR4 and ChR in the hindbrain reticulospinal V2a neurons, which are involved in locomotion, induced swimming behavior at relatively short latencies, whereas activation of GC1 or PACs achieved it at long latencies.

Optogenetic manipulation of Gq- and Gi/o-coupled receptor signaling in neurons and heart muscle cells.

G-protein-coupled receptors (GPCRs) transmit signals into cells depending on the G protein type. To analyze the functions of GPCR signaling, we assessed the effectiveness of animal G-protein-coupled bistable rhodopsins that can be controlled into active and inactive states by light application using zebrafish. We expressed Gq- and Gi/o-coupled bistable rhodopsins in hindbrain reticulospinal V2a neurons, which are involved in locomotion, or in cardiomyocytes.