Dr. Satchin Panda was born and raised in India, where he earned his bachelor's degree in plant biology from Orissa University of Agriculture and Technology. He joined the graduate program at the Scripps Research Institute in California, where he studied the circadian oscillator mechanism in plants in the laboratory of Dr. Steve Kay. Since receiving his PhD in 2001, he has pursued postdoctoral research in Dr. John Hogenesch's lab at the Genomics Institute of the Novartis Research Foundation, San Diego. Here he uses genetic and genomic approaches to gain an understanding of the light input pathway, as well as circadian regulation of behavior and physiology in mammals. His work has demonstrated tissue-specific circadian regulation of transcription, and it has elucidated a complex mechanism by which mammals recruit multiple photoreceptors to adapt to their natural environment.
Shedding light on non-image-forming photo perception in mammals.
Although mice lacking rod and cone photoreceptors are blind, they retain many eye-mediated responses to light, possibly through photosensitive retinal ganglion cells (RGC). These cells express melanopsin (Opn4), a photopigment that confers this photosensitivity. Mice lacking melanopsin (Opn4-/-) still retain nonvisual photoreception, suggesting that rods and cones could operate in this capacity. We observed that mice with both outer retinal degeneration and a deficiency in melanopsin exhibited: complete loss of photoentrainment of the circadian oscillator and pupillary light responses; photic suppression of arylalkylamine-N-acetyltransferase (AA-NAT) transcript; and acute suppression of locomotor activity by light. This indicates the importance of both nonvisual and classical visual photoreceptor systems for nonvisual photic responses in mammals.
For Dr. Panda’s full essay, see Science Online at sciencemag.org.