Congratulations to winners of the Nobel Prize in Physiology or Medicine 2017: Jeffrey C. Hall, Michael Rosbash, Michael W. Young for their discoveries of molecular mechanisms controlling the circadian rhythm.
Circadian aspects of adipokine regulation in rodents. Challet E, Best Practice & Research Clinical Endocrinology & Metabolism (2017), doi: 10.1016/j.beem.2017.09.003.
This paper reviews reciprocal links between the circadian clocks and rhythmic secretion of leptin, and discusses the metabolic impact of circadian desynchronization and altered rhythmic leptin. The authors report that leptin is well-known to modulate the timing of food intake by its anorectic effects mostly mediated by the arcuate nuclei of the hypothalamus. They cite a report by Li et al. (1) demonstrating damage to the arcuate neurons expressing leptin receptors by local injections of Leptin-SAP (Cat. #IT-47) leads to hyperphagia coupled to arrhythmic pattern of feeding.
Wiater MF, Li AJ, Dinh TT, Jansen HT, Ritter S. (2013) Leptin-sensitive neurons in the arcuate nucleus integrate activity and temperature circadian rhythms and anticipatory responses to food restriction. Am J Physiol Regul Integr Comp Physiol 305(8):R949-R960.
Li AJ, Wiater MF, Oostrom MT, Smith BR, Wang Q, Dinh TT, Roberts BL, Jansen HT, Ritter S. (2012) Leptin-sensitive neurons in the arcuate nuclei contribute to endogenous feeding rhythms. Am J Physiol Regul Integr Comp Physiol 302(11):R1313-26.
Targeting Cells that Affect Circadian Clocks
Melanopsin-SAP (Cat. #IT-44) specifically eliminates intrinsically photosensitive retinal ganglion cells (ipRGCs) that contain melanopsin. The ipRGCs, with their amazing long processes are major players in the perception of light and dark, and their role as circadian rhythm determinants is a hot topic.
Göz D, Studholme K, Lappi DA, Rollag MD, Provencio I, Morin LP PLoS One 3(9), e3153, 2008
Dyno-SAP (Dynorphin-SAP) (Cat. #IT-68) eliminates kappa-opioid receptor expressing cells. Dynorphin has many different physiological actions, including analgesia, addiction, appetite, circadian rhythms, stress, and depression.
Mistlberger RE, Antle MC, Kilduff TS, Jones M (2003) Food- and light-entrained circadian rhythms in rats with hypocretin-2-saporin ablations of the lateral hypothalamus. Brain Res 980(2):161-168.
Wiater MF, Mukherjee S, Li AJ, Dinh TT, Rooney EM, Simasko SM, Ritter S. (2011) Circadian Integration of Sleep/Wake and Feeding Requires NPY-Receptor Expressing Neurons in the Mediobasal Hypothalamus. Am J Physiol Regul Integr Comp Physiol 301(5):R1569-83.