Circadian system: neural network with suprachiasmatic nucleus at the top of a hierarchical organization
Abstract
Biological rhythms represent series of events occurring repeatedly in the same order and time intervals in all living beings including humans. All eukaryotes show variabilities in the genetic (rhythm of DNA and RNA synthesis, mitosis rhythm), biochemical (metabolic rhythms) and physiological (rhythm of synthesis and secretion of certain hormones, menstrual cycle, rhythmic body temperature changes, heart rate, breathing frequency, the sleep/wake cycle, work and rest, etc.) functions by enhancing and reducing their activities throughout cycles. Circadian oscillator genesis is based on combination of negative feedbacks, clock gene expression and translation of proteins that control temporal sequences of cell metabolic processes. Clock genes have been discovered: per (periodic) and tim (timeless), and they encode the information for synthesis of two proteins named the same as previously mentioned genes. These proteins accumulate in the cell during the night and degrade during day. Their concentration oscillates in 24h long cycles, synchronously with the circadian rhythm. For this discovery, American scientists received a Nobel Prize in Physiology or Medicine in 2017. With excellent precision, our internal clock regulates critical functions such as behavior, hormone secretion, sleep, body temperature, metabolism, and other functions. By doing this they adjust the physiological functions to different stages of the day, increase the activity of SCN neurons that regulate wakefulness / slow wave sleep and control the endogenous clock. The pineal gland is in direct contact with the endogenous clock and produces hormone melatonin that causes drowsiness. The melatonin concentration is decreased or is not measurable during the day. Light, pineal gland and melatonin regulate the sleep cycle, and each disturbance of this components leads to dysfunctions.
Key words: biological rhytms, endogenous clock, pineal gland, melatonin
References
Saini C, Brown SA, Dibner C. Human peripheral clocks: applications for studying circadian phenotypes in physiology and pathophysiology. Front Neurol. 2015; 6:95.2.
Roenneberg T, Kuehnle T, Juda M, Kantermann T, Allebrandt K, Gordijn M, et al. Epidemiology of the human circadian clock. Sleep Med Rev. 2007 Dec; 11(6):429-438.
Cloudsley - Thompson JL. Microecology. Studies in Biology 6, E.Arnold Publ, London:49, 1967.
Luce GG. Biological Rhythms in Human and Animal Physiology By G.G. Luce (183) Dover Publications: New York. 1972.
DeMairan J. Observation botanique. Hist Acad Roy Sci, 35–36, 1729.
Stearn, WT. The background of linnaeus’s contributions to the nomenclature and methods of systematic biology. Systematic Biology. 1959 March; 8(1):4–22.
Müller-Wille S, Orel V. From Linnaean Species to Mendelian Factors: Elements of Hybridism, 1751–1870. Annals of Science 2007; 64:171-215.
Silver R and Rainbow M. The Suprachiasmatic Nucleus and the Circadian Timekeeping System of the Body. Neuroscience in the 21st Century, D.W. Pfaff (ed.) 1-49, 2015.
Moran D, Softley R, Warrant EJ. Eyeless Mexican cavefish save energy by eliminating the circadian rhythm in metabolism. PLoS One. 2014 Sep; 9(9):e107877.
Reinberg EA and Smolensky HM. Night and Shift Work and Transmeridian and Space Flights, 243-255, 1992.
Halber F. The 24-hour scale: a time dimension of adaptive functional organization. Perspect Biol Med. 1960; 3:491-527.
van Oosterhout F, Lucassen EA, Houben T, vanderLeest HT, Antle MC, Meijer JH. Amplitude of the SCN clock enhanced by the behavioral activity rhythm. PLoS One. 2012; 7(6):e39693.
Vansteensel MJ, Michel S, Meijer JH. Organization of cell and tissue circadian pacemakers: a comparison among species. Brain Res Rev. 2008 Jun; 58(1):18-47.
Charrier A, Olliac B, Roubertoux P, Tordjman S. Clock Genes and Altered Sleep–Wake Rhythms: Their role in the development of psychiatric disorders. Int J Mol Sci. 2017 Apr; 18(5):pii:E938.
Okamoto S, Okamura H, Miyake M, Takahashi Y, Takagi S, Akagi K, et al. A diurnal variation of vasoactive intestinal peptide (VIP) mRNA under a daily light-dark cycle in the rat suprachiasmatic nucleus. Histochemistry. 1991; 95(5):525-528.
Wray S, Castel N, Gamer H. Characterization of the suprachiasmatic nucleus in organotypic slice explant cultures. Microsc Res Tech. 1993 May; 25(1):46-60.
Hannibal J. Neurotransmitters of the retino-hypothalamic tract. Cell Tissue Res. 2002 Jul; 309(1):73-88.
Reghunandanan V, Reghunandanan R. Neurotransmitters of the suprachiasmatic nuclei. J Circadian Rhythms. 2006 Feb;4:2.
Vriend J, Reiter RJ. Melatonin feedback on clock genes: a theory involving the proteasome. J Pineal Res. 2015 Jan; 58(1):1-11.
Graham DM, Wong KY. Melanopsin-expressing, Intrinsically Photosensitive Retinal Ganglion Cells (ipRGCs). Webvision: The Organization of the Retina and Visual System 2008 In: Kolb H, Fernandez E, Nelson R, editors.
Nováková M, Sládek M, Sumová A. Human chronotype is determined in bodily cells under real-life conditions. Chronobiol Int. 2013 May; 30(4):607-617.
Stokkan KA, Yamazaki S, Tei H, Sakaki Y, Menaker M. Entrainment of the circadian clock in the liver by feeding. Science. 2001 Jan; 291(5503):490-493.
Carcieri SM, Jacobs AL, Nirenberg S. Classification of retinal ganglion cells: a statistical approach. J Neurophysiol. 2003 Sep; 90(3):1704-13.
Wang YP, Dakubo G, Howley P, Campsall KD, Mazarolle CJ, Shiga SA, et al. Development of normal retinal organization depends on Sonic hedgehog signaling from ganglion cells. Nat Neurosci. 2002 Sep; 5(9):831-832.
Zochowski M, Wachowiak M, Falk CX, Cohen LB, Lam YW, Antic S, et al. Imaging membrane potential with voltage-sensitive dyes. Biol Bull. 2000 Feb; 198(1):1-21.
Johansson AS, Owe-Larsson B, Hetta J, Lundkvist GB. Altered circadian clock gene expression in patients with schizophrenia. Schizophr Res. 2016 Jul; 174(1-3):17-23.
Buhr ED, Takahashi JS. Molecular components of the Mammalian circadian clock. Handb Exp Pharmacol. 2013; (217):3-27.
Berson DM. Strange vision: ganglion cells as circadian photoreceptors. Trends Neurosci. 2003 Jun; 26(6):314-320.
Hattar S, Liao HW, Takao M, Berson DM, Yau KW. Melanopsin-containing retinal ganglion cells: architecture, projections, and intrinsic photosensitivity. Science. 2002 Feb; 295(5557):1065-70.
Lerner A, Case, JD, Takahashi Y, Lee TH, Mori W. Isolation of melatonin, a pineal factor that lightens melanocytes. J Am Chem Soc. 1958 May; 80(10): 2587.
Jerison HJ. Evolution of the Brain and Intelligence. New York: Academic Press; 1973.
Satjananda SS. The pineal gland (ajnachakra). Bihar India: Bihar school of Yoga; 1972.
Maronde E, Stehle JH. The mammalian pineal gland: known facts, unknown facets. Trends Endocrinol Metab. 2007 May-Jun; 18(4):142-9.
Weaver DR. The suprachiasmatic nucleus: a 25-year retrospective. J Biol Rhythms. 1998 Apr; 13(2):100-12.
Hardeland R, Cardinali DP, Srinivasan V, Spence DW, Brown GM, Pandi-Perumal SR. Melatonin--a pleiotropic, orchestrating regulator molecule. Prog Neurobiol. 2011 Mar; 93(3):350-84.
Pandi-Perumal SR, Trakht I, Srinivasan V, Spence DW, Maestroni GJ, Zisapel N, et al. Physiological effects of melatonin: role of melatonin receptors and signal transduction pathways. Prog Neurobiol. 2008 Jul; 85(3):335-53.
Aschoff J. Exogenous and endogenous components in circadian rhythms. Cold Spring Harbor Symposia on Quantitative Biology: Volume XXV. Biological Clocks. New York: Cold Spring Harbor Press,11–28, 1960.
Back FA, Fortes FS, Santos EHR, Barreto LSM, Louzada FM. Non-photic synchronization: the effect of aerobic physical exercise. Rev. Bras. Med. Esporte, 13:123-124, 2007.
Vitaterna MH, Takahashi JS, Turek FW. Overview of circadian rhythms. Alcohol Res Health. 2001; 25(2):85-93.
Ditisheim AJ, Dibner C, Philippe J, Pechère-Bertschi A. Biological rhythms and preeclampsia. Front Endocrinol (Lausanne). 2013 Apr 8; 4:47.
Brown DL, Feskanich D, Sánchez BN, Rexrode KM, Schernhammer ES, Lisabeth LD. Rotating night shift work and the risk of ischemic stroke. Am J Epidemiol. 2009 Jun 1; 169(11):1370-7.
Baehr EK, Fogg LF, Eastman CI. Intermittent bright light and exercise to entrain human circadian rhythms to night work. Am J Physiol. 1999 Dec; 277(6 Pt 2):R1598-604.
Reppert SM, Weaver DR. Molecular analysis of mammalian circadian rhythms. Annu Rev Physiol. 2001; 63:647-676.
Youngstedt SD, Kripke DF, Elliott JA. Circadian phase-delaying effects of bright light alone and combined with exercise in humans. Am J Physiol Regul Integr Comp Physiol. 2002 Jan; 282(1):R259-66.
Takahashi JS, Hong HK, Ko CH, McDearmon EL. The genetics of mammalian circadian order and disorder: implications for physiology and disease. Nat Rev Genet. 2008 Oct; 9(10):764-775.
Smarr BL, Schirmer AE. 3.4 million real-world learning management system logins reveal the majority of students experience social jet lag correlated with decreased performance. Sci Rep. 2018 Mar 29; 8(1):4793.
Smolensky MH, Scott PH, Harrist RB, Hiatt PH, Wong TK, Baenziger JC, et al. Administration-time-dependency of the pharmacokinetic behavior and therapeutic effect of a once-a-day theophylline in asthmatic children. Chronobiol Int. 1987; 4(3):435-447.
Mormont MC, Levi F. Cancer chronotherapy: principles, applications, and perspectives. Cancer. 2003 Jan 1; 97(1):155-169.
Borbély AA, Achermann P. Sleep homeostasis and models of sleep regulation. J Biol Rhythms. 1999 Dec; 14(6):557-568.