Pineal glandThe pineal gland (also known as the pineal body, conarium, or epiphysis cerebri) is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two hemispheres, tucked in a groove where the two halves of the thalamus join.
NorepinephrineNorepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin ad, "near", and ren, "kidney") is more commonly used in the United Kingdom, whereas "norepinephrine" (from Ancient Greek ἐπῐ́ (epí), "upon", and νεφρός (nephrós), "kidney") is usually preferred in the United States. "Norepinephrine" is also the international nonproprietary name given to the drug.
Circadian rhythm sleep disorderCircadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep-wake disorders (CRSWD), are a family of sleep disorders which affect the timing of sleep. CRSDs arise from a persistent pattern of sleep/wake disturbances that can be caused either by dysfunction in one's biological clock system, or by misalignment between one's endogenous oscillator and externally imposed cues. As a result of this mismatch, those affected by circadian rhythm sleep disorders have a tendency to fall asleep at unconventional time points in the day.
Circadian rhythmA circadian rhythm (sərˈkeɪdiən), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment (is entrained by the environment). Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximise the fitness of an individual.
Suprachiasmatic nucleusThe suprachiasmatic nucleus or nuclei (SCN) is a small region of the brain in the hypothalamus, situated directly above the optic chiasm. It is the principal circadian pacemaker in mammals and is necessary for generating circadian rhythms. Reception of light inputs from photosensitive retinal ganglion cells allow the SCN to coordinate the subordinate cellular clocks of the body and entrain to the environment. The neuronal and hormonal activities it generates regulate many different body functions in an approximately 24-hour cycle.
Delayed sleep phase disorderDelayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is the delaying of a person's circadian rhythm (biological clock) compared to those of societal norms. The disorder affects the timing of biological rhythms including sleep, peak period of alertness, core body temperature, and hormonal cycles. The diagnosis of this disorder is currently a point of contention among specialists of sleep disorders.
Intrinsically photosensitive retinal ganglion cellIntrinsically photosensitive retinal ganglion cells (ipRGCs), also called photosensitive retinal ganglion cells (pRGC), or melanopsin-containing retinal ganglion cells (mRGCs), are a type of neuron in the retina of the mammalian eye. The presence of (something like) ipRGCs was first suspected in 1927 when rodless, coneless mice still responded to a light stimulus through pupil constriction, This implied that rods and cones are not the only light-sensitive neurons in the retina.
Melatonin as a medication and supplementMelatonin is a dietary supplement and medication as well as naturally occurring hormone. As a hormone, melatonin is released by the pineal gland and is involved in sleep–wake cycles. As a supplement, it is often used for the attempted short-term treatment of disrupted sleep patterns, such as from jet lag or shift work, and is typically taken orally. Evidence of its benefit for this use, however, is not strong. A 2017 review found that sleep onset occurred six minutes faster with use, but found no change in total time asleep.
TryptophanTryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic beta carbon substituent. Tryptophan is also a precursor to the neurotransmitter serotonin, the hormone melatonin, and vitamin B3. It is encoded by the codon UGG. Like other amino acids, tryptophan is a zwitterion at physiological pH where the amino group is protonated (–NH3+; pKa = 9.
Circadian clockA circadian clock, or circadian oscillator, is a biochemical oscillator that cycles with a stable phase and is synchronized with solar time. Such a clock's in vivo period is necessarily almost exactly 24 hours (the earth's current solar day). In most living things, internally synchronized circadian clocks make it possible for the organism to anticipate daily environmental changes corresponding with the day–night cycle and adjust its biology and behavior accordingly.
Entrainment (chronobiology)In the study of chronobiology, entrainment occurs when rhythmic physiological or behavioral events match their period to that of an environmental oscillation. It is ultimately the interaction between circadian rhythms and the environment. A central example is the entrainment of circadian rhythms to the daily light–dark cycle, which ultimately is determined by the Earth's rotation. Exposure to certain environmental stimuli will cue a phase shift, and abrupt change in the timing of the rhythm.
Phase response curveA phase response curve (PRC) illustrates the transient change (phase response) in the cycle period of an oscillation induced by a perturbation as a function of the phase at which it is received. PRCs are used in various fields; examples of biological oscillations are the heartbeat, circadian rhythms, and the regular, repetitive firing observed in some neurons in the absence of noise. In humans and animals, there is a regulatory system that governs the phase relationship of an organism's internal circadian clock to a regular periodicity in the external environment (usually governed by the solar day).
IndoleIndole is an aromatic, heterocyclic, organic compound with the formula . It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environment and can be produced by a variety of bacteria. As an intercellular signal molecule, indole regulates various aspects of bacterial physiology, including spore formation, plasmid stability, resistance to drugs, biofilm formation, and virulence.
Shift work sleep disorderShift work sleep disorder (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive sleepiness, or both affecting people whose work hours overlap with the typical sleep period. Insomnia can be the difficulty to fall asleep or to wake up before the individual has slept enough. About 20% of the working population participates in shift work. SWSD commonly goes undiagnosed, so it's estimated that 10–40% of shift workers have SWSD. The excessive sleepiness appears when the individual has to be productive, awake and alert.
Retinohypothalamic tractIn neuroanatomy, the retinohypothalamic tract (RHT) is a photic neural input pathway involved in the circadian rhythms of mammals. The origin of the retinohypothalamic tract is the intrinsically photosensitive retinal ganglion cells (ipRGC), which contain the photopigment melanopsin. The axons of the ipRGCs belonging to the retinohypothalamic tract project directly, monosynaptically, to the suprachiasmatic nuclei (SCN) via the optic nerve and the optic chiasm.
Non-24-hour sleep–wake disorderNon-24-hour sleep–wake disorder (non-24 or N24SWD) is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising [...] daily delays in sleep onset and wake times in an individual living in a society". Symptoms result when the non-entrained (free-running) endogenous circadian rhythm drifts out of alignment with the light–dark cycle in nature. Although this sleep disorder is more common in blind people, affecting up to 70% of the totally blind, it can also affect sighted people.
Gq alpha subunitDISPLAYTITLE:Gq alpha subunit Gq protein alpha subunit is a family of heterotrimeric G protein alpha subunits. This family is also commonly called the Gq/11 (Gq/G11) family or Gq/11/14/15 family to include closely related family members. G alpha subunits may be referred to as Gq alpha, Gαq, or Gqα. Gq proteins couple to G protein-coupled receptors to activate beta-type phospholipase C (PLC-β) enzymes. PLC-β in turn hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) to diacyl glycerol (DAG) and inositol trisphosphate (IP3).
Gi alpha subunitDISPLAYTITLE:Gi alpha subunit Gi protein alpha subunit is a family of heterotrimeric G protein alpha subunits. This family is also commonly called the Gi/o (Gi /Go ) family or Gi/o/z/t family to include closely related family members. G alpha subunits may be referred to as Gi alpha, Gαi, or Giα. There are four distinct subtypes of alpha subunits in the Gi/o/z/t alpha subunit family that define four families of heterotrimeric G proteins: Gi proteins: Gi1α, Gi2α, and Gi3α Go protein: Goα (in mouse there is alternative splicing to generate Go1α and Go2α) Gz protein: Gzα Transducins (Gt proteins): Gt1α, Gt2α, Gt3α Gi1α is encoded by the gene GNAI1.
Natural productA natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical synthesis (both semisynthesis and total synthesis) and have played a central role in the development of the field of organic chemistry by providing challenging synthetic targets.
Endocrine glandEndocrine glands are ductless glands of the endocrine system that secrete their products, hormones, directly into the blood. The major glands of the endocrine system include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands. The hypothalamus and pituitary glands are neuroendocrine organs. Pituitary gland The pituitary gland hangs from the base of the brain by the pituitary stalk, and is enclosed by bone.
