THE PHYSIOLOGICAL FUNCTION OF OPN5-EXPRESSING NEURONS IN THE PREOPTIC AREA

Modern lighting environments differ markedly from natural sunlight, particularly in their deficiency of violet light (360–400 nm). This spectral gap may have unforeseen physiological consequences. Opsin 5 (OPN5), also known as neuropsin, is a conserved purple/ultraviolet (UV)-sensitive G protein-coupled receptor (GPCR) in vertebrates. Mammalian OPN5 functions as a non-visual photopigment and is expressed in diverse extra-retinal tissues such as skin, testes, and several deep brain regions. However, its physiological role remains largely unclear.
In this study, we successfully established two new mouse lines, “OPN5-2A-CreERT2” and “OPN5-mGLx3,” for analyzing the physiological functions of OPN5. These mice enable the specific expression of a gene in OPN5-expressing cells and the visualization of OPN5-expressing cells, respectively. Using these mice and viral vectors, we histochemically elucidated input and output neural pathways to/from OPN5-expressing neurons in the preoptic area (POA). We also selectively manipulated the activity and cell fate of these neurons to clarify their impact on thermoregulation. Furthermore, patch-clamp activity recordings from OPN5-expressing neurons showed that these neurons directly respond to violet light through OPN5.
These in vivo and in vitro experiment results using newly generated mice revealed the physiological function of OPN5-expressing neurons in the POA.