The following is a summary of the “Retinal TRP channels: Cell-type-specific regulators of retinal homeostasis and multimodal integration,” published in the January 2023 issue of Progress in retinal and eye research by Križaj, et al.

To function as primary detectors of chemical and physical stimuli and secondary effectors of metabotropic and ionotropic receptors, cells express 28 cationic ion channels known as transient receptor potential (TRP) channels. There are six families of channels found in vertebrates, and they are denoted by the letters TRPC, TRRPV, TRPM, TRPA, TRPML, and TRPP. TRP channels mediate crucial functions in mechanosensation, nociception, chemosensation, thermosensation, and phototransduction and are widely expressed throughout the body and the CNS. 

In this article, they take stock of what is known about the expression and function of the TRP family in vertebrate retinas, which, despite being specialized for the transduction and transmission of visual information, are also highly sensitive to stimuli that are not visual. All retinal cells express multiple TRP subunits, and recent evidence has established their crucial roles in several paradigmatic aspects of vertebrate vision, such as TRPM1-dependent transduction of ON bipolar signaling, TRPC6/7-mediated ganglion cell phototransduction, TRP/TRPL phototransduction in Drosophila, and TRPV4-dependent osmoregulation, mechanotransduction, and regulation of inner and outer blood-retina barriers. 

Growing evidence suggests that particular subunits of TRP channels play a role in the pathogenesis of blinding conditions like glaucoma, ocular trauma, diabetic retinopathy, and ischemia by tuning the intracellular concentration of the 2nd messenger calcium. Gains in basic knowledge of vertebrate vision and therapeutic targeting to treat diseases caused by channel dysfunction or over-activation are expected from the elucidation of TRP channel involvement in retinal biology.

Source: sciencedirect.com/science/article/abs/pii/S135094622200074X