Body temperature, and sleep

Neurotransmitters are chemicals that carry messages, or signals, from a nerve cell to a target cell, which may be another nerve cell or a muscle cell. They may be inhibitory or excitatory and all are nitrogen-containing compounds. The catecholamines include dopamine, norepinephrine, and epinephrine. Too little dopamine results in Rarkinson s disease. Too much is associated with schizophrenia. Dopamine is also associated with addictive behavior. A deficiency of serotonin is associated with depression and eating disorders. Serotonin is involved in pain perception, regulation of body temperature, and sleep. Histamine contributes to al-... 

Hypothalamus A gland in the brain that controls hunger, thirst, body temperature, and sleep cycles. 

POA WSNs also initiates thermolytic autonomic processes with resulting heat loss. It is reasonable to speculate that the activation of these neurons underlies the peripheral vasodilation and evoked lowering of body temperature at sleep onset (reviewed by Heller, 2005) and the association of high sleep propensity with the low-body-temperature phase of the circadian temperature cycle... 

Dollins, A. B., Zhdanova, I. V., Wurtman, R. J., Lynch, H. J. Deng, M. H. (1994). Effect of inducing nocturnal serum melatonin concentrations in daytime on sleep, mood, body temperature, and performance. Proc. Natl. Acad. Sci. USA 91, 1824-8. 

Circadian Sieep Rhythm. Sleep can be conceptualized as a pair of cycles each regulated by a biological clock. The larger cycle is the rhythm of sleep and wakefulness that operates according to a 24 hour (circadian) biological clock. The sleep-wake cycle is not our only circadian rhythm. Body temperature and certain hormones fluctuate in accordance with this same biological rhythm. 

Jet lag, a disturbance of the sleep-wake cycle, occurs when there is a disparity between the external time and the traveler s endogenous circadian clock (internal time). The internal time regulates not only daily sleep rhythms but also body temperature and many metabolic systems. The synchronization of the circadian clock relies on light as the most potent "zeitgeber" (time giver). 

Brun et al. (216) evaluated the mental performance, hormone levels, and temperatures of eight sleep-deprived volunteers given 300-mg of modafinil at 22 00 and 08 00. Modafinil did not affect melatonin, cortisol, or growth hormone levels, but it did attenuate performance decrements, attenuate the nocturnal decrease in body temperature, and increase daytime body temperature. These temperature effects are different from what has been observed in non-sleep-deprived subjects. Bourdon et al. (217) found no effects of 200 mg of modafinil on thermal balance in neutral conditions and no effect on thermoregulation in cold conditions (despite a tendency toward greater reductions in core temperature when modafinil was applied in a cold environment). However, these authors did not examine temperature effects beyond 3 hr in the morning. The differences with... 

Pigeau R, Naitoh P, Buguet A, McCann C, Baranski J, Taylor M, Thompson M, Mack I. Modafinil, 4-amphetamine and placebo during 64 hours of sustained mental work. I. Effects on mood, fatigue, cognitive performance and body temperature. J Sleep Res 1995 4 212-228. 

Lack LC, Lushington K. The rhythms of human sleep propensity and core body temperature. J Sleep Res 1996 5 1-11. 

The biological function of amine oxidases involves the oxidation of biogenic amines formed during normal biological processes. In mammals, the monoamine oxidases are involved in the control of the serotonin catecholamine ratios in the brain, which in turn influence sleep and EEG patterns, body temperature, and mental depression. Two groups of amine oxidases are involved in the oxidative deamination of naturally occurring amines as well as foreign compounds. 

Bacterial infections elicit a series of acute-phase responses which include central nervous system effects such as changes in body temperature and increased slow-wave sleep. Dead bacteria [54] and murein preparations [55] as well as other bacterial cell-wall products induce similar responses. Intravenous injections of rabbits with suspensions of pseudomurein from Methanobacterium thermoautotrophicum also alter sleep and brain temperature. The mechanisms responsible for these somnogenic and pyrogenic effects are unknown [56]. It has been demonstrated that in a rat arthritis model, intra-articular injection of high doses of pseudomurein-polysaccharide fragments from Methanobacterium formicicum caused an acute inflammation [57]. 

In the brain, serotonergic neurons are located in the brainstem in clusters of cells called the raphe nuclei, within which is the reticular network. These serotonergic neurons send their axonal projections throughout the entire brain. As a neurotransmitter, serotonin is involved in the regulation of numerous behavioral and physiological processes, including mood, appetite, sleep, sexual function, blood flow, body temperature, and more. The fact that both tryptophan and 5-HTP are chemical precursors for the synthesis of serotonin is presumably the reason for the claim of their efficacy in the treatment of problems related to mood, sleep, and appetite (Murray 1999). 

Several investigations have studied the in vivo antidepressant activity of this herb and of compounds isolated from it. For example, a commercially available extract of the aerial parts of Hypericum perforatum LI 160 and hypericin, Fig. (13) showed pronounced activity in selected animal bioassays. These include the forced swimming test and the tail suspension test, used to determine antidepressant activity, and tests indicating activity on the central nervous system, such as body temperature and ketamine-induced sleeping time [231,232],... 

Melatonin, a naturally occurring amide, is a hormone that is synthesized hy the pineal gland from the amino acid tryptophan. Melatonin regulates the dark-light clock that governs such things as the sleep-wake cycle, body temperature, and hormone production. 

The body positions/leg movements and body temperature during sleep are typically also recorded. The entirety of the recorded values gives a very accurate sleep profile of the person and allows one to draw reliable conclusions about a sleep disorder. This section gives a brief introduction to the individual recordings. 

Serotonin has been found to influence sleeping, the regulation of body temperature, and sensory perception, but its exact role in mental illness is not yet clear. Unusually low levels of 5-hydroxyindoleacetic acid, a product of serotonin utilization, are characteristically found in the spinal fluid of victims of violent suicide. Drugs that mimic serotonin are sometimes used to treat depression, anxiety, and obsessive-compulsive disorder. Serotonin blockers are used to treat migraine headaches and relieve the nausea that accompanies cancer chemotherapy. A better understanding of the biochemistry of the brain may lead to better medications for treating various forms of mental illness. 

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