AUTHOR=Dan William , Park Ga Hyun , Vemaraju Shruti , Wu Amy D. , Perez Kristina , Rao Meenakshi , Berkowitz Dan E. , Lang Richard A. , Yim Peter D. 

TITLE=Light-Mediated Inhibition of Colonic Smooth Muscle Constriction and Colonic Motility via Opsin 3

JOURNAL=Frontiers in Physiology

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2021.744294

DOI=10.3389/fphys.2021.744294

ISSN=1664-042X

ABSTRACT=Opsin photoreceptors outside of the central nervous system have been shown to mediate smooth muscle photorelaxation in several organs. We hypothesized that opsin receptor activation in the colon would have a similar effect and influence colonic motility. We detected Opsin 3 (OPN3) protein expression in the colonic wall and demonstrated that OPN3 was present in enteric neurons in the muscularis propria of the murine colon. Pre-contracted murine colon segments demonstrated blue light mediated relaxation ex vivo. This photorelaxation was wavelength specific and was increased with the administration of the chromophore 9-cis retinal and a G protein receptor kinase 2 inhibitor. Light mediated relaxation of the colon was not inhibited by L-NAME or tetrodotoxin. Furthermore, blue light exposure in the presence of 9-cis retinal decreased the frequency of colonic migrating motor complexes in spontaneously contracting mouse colons ex vivo. These results demonstrate for the first time a receptor mediated photorelaxation of colonic smooth muscle and implicate opsins as possible new targets in the treatment of spasmodic gastrointestinal dysmotility.