Retineal

Retineal is a chemical compound, specifically an aldehyde derived from vitamin A. It plays a crucial role in the process of vision within the eyes of many organisms. When light strikes the retina, retineal undergoes a change in its molecular shape. This transformation is the initial step in a biochemical cascade that ultimately leads to the transmission of a signal to the brain, allowing us to perceive sight. Retineal exists in different isomeric forms, with the most biologically relevant being 11-cis-retineal. This particular isomer is bound to proteins called opsins within photoreceptor cells, forming chromophores essential for light detection. Upon light absorption, 11-cis-retineal isomerizes to all-trans-retineal, triggering the visual transduction pathway. Retineal is regenerated within the eye through a cycle known as the visual cycle, ensuring a continuous supply for vision. Its importance extends beyond vision, as retinoids, which are related to retineal, are also involved in cell growth, differentiation, and immune function.