Publications by authors named "Richard J McDowell"
Article Synopsis
- Light plays a crucial role in regulating the physiology and behavior of mammals, and improper light exposure can lead to health issues due to disrupted circadian rhythms.
- The study introduces a new method for measuring light using a photoreceptor-specific (α-opic) approach that accounts for variations across different mammalian species and their unique photoreceptor types.
- Results show that α-opic measurements provide better predictions of physiological responses to light than the traditional lux measurements, potentially enhancing animal welfare, scientific research, agriculture, and energy efficiency.
Light enables vision and exerts widespread effects on physiology and behavior, including regulating circadian rhythms, sleep, hormone synthesis, affective state, and cognitive processes. Appropriate lighting in animal facilities may support welfare and ensure that animals enter experiments in an appropriate physiological and behavioral state. Furthermore, proper consideration of light during experimentation is important both when it is explicitly employed as an independent variable and as a general feature of the environment.
View Article and Find Full Text PDFPatterns of diel activity-how animals allocate their activity throughout the 24-h daily cycle-play key roles in shaping the internal physiology of an animal and its relationship with the external environment. Although shifts in diel activity patterns have occurred numerous times over the course of vertebrate evolution, the genomic correlates of such transitions remain unknown. Here, we use the African striped mouse (Rhabdomys pumilio), a species that transitioned from the ancestrally nocturnal diel niche of its close relatives to a diurnal one, to define patterns of naturally occurring molecular variation in diel niche traits.
View Article and Find Full Text PDFMelanopsin is an opsin photopigment and light-activated G-protein-coupled receptor; it is expressed in photoreceptive retinal ganglion cells (mRGCs) and can be employed as an optogenetic tool. Mammalian melanopsins can signal via Gq/11 and Gi/o/t heterotrimeric G proteins, but aspects of the mRGC light response appear incompatible with either mode of signalling. We use live-cell reporter assays in HEK293T cells to show that melanopsins from mice and humans can also signal via Gs.
View Article and Find Full Text PDFArticle Synopsis
- - Xenopsin, a new subtype of opsin photopigment, challenges previous beliefs about the evolution of opsins and photoreceptors, suggesting it diverged from ciliary opsins long before bilaterians existed.
- - A study in flatworms revealed that xenopsin is found in both ciliary cells of larval eyes and extraocular cells in adult brains, with extraocular cells containing many cilia in a structure called a phasosome.
- - Functional tests in human cells indicate that xenopsin mainly drives phototransduction by connecting to Gαi, showing similarities to c-opsin and revealing a new type of opsin-expressing cell comparable to rods in vertebrates.