Pineal system melatonin

In patients with DSPS, a delay in the timing of physiological and behavioral systems that demonstrate circadian rhythmicity is reported, compared to normally entrained individuals. This delay is evident in a variety of functions, including secretion of the pineal hormone melatonin (e.g., Ref. 162), thermoregulation, and sleep-wake activity. Individuals with DSPS typically experience difficulty initiat-... 

The pineal hormone melatonin inhibits the production of free radicals that mediate the toxicity of chemotherapy. The main objective of this prototype drug-deHvery system was to develop and evaluate a novel occlusive bioadhesive system for prophylaxis and/or treatment of oral mucositis based on chitosan, melatonin and propoHs in order to exploit natural biomaterials as functional biocompatible gels [35,40],... 

However, despite its enormous importance to human physiology, no pharmacological compounds targeting the components of the circadian clock system have been identified to date. There are, nevertheless, two therapeutic approaches that are currently used for treatment of circadian-related disorders - full-spectrum and bright light therapy and melatonin therapy. Melatonin is a hormone that is produced by the pineal gland in... 

Serotonin is present in a variety of sites in the brain. Its role as a neurotransmitter and its relation to the actions of drugs acting in the central nervous system are discussed in Chapters 21 and 30. Serotonin is also a precursor of melatonin in the pineal gland (Figure 16-2 ... 

There are many nerve fibers in the pineal gland. Some of these fibers release noradrenalin, a chemical messenger produced by the nervous system. Noradrenalin stimulates certain cells in the pineal gland, called pinealocytes, to produce and release melatonin. 

One further treatment that has been studied extensively to achieve resynchronization of the circadian system is the administration of melatonin. Endogenous melatonin is secreted from the pineal gland, primarily across the nocturnal or dark period. It has been proposed to play a role in the control of the circadian system (reviewed in Ref. 174) and potentially in the initiation of sleep (175,176). Studies that have administered exogenous melatonin, primarily during the daytime, have reported both chronobiotic (177) and soporific effects (178). Melatonin administration has been successful in studies examining the reentrainment of the circadian system after transmeridian flight or shiftwork (179). Similarly, the effectiveness of melatonin in reentraining the circadian system of those with DSPS to a normal day has been studied. 

Koyama FC, Ribeiro RY, Garcia JL et al (2012) Ubiquitin proteasome system and the atypical kinase PfPK7 are involved in melatonin signaling in Plasmodium falciparum. J Pineal Res Jan 30 [Epub ahead of print] doi 10.111 l/j,1600-079X.2012.00981.x... 

The permissive serotonin hypothesis proposes that serotonin (5-hydroxytryptamine or 5-HT) plays a critical role in modulating brain activity (e.g., stabilization of the catecholamine system and inhibition of dopamine [DA] release), and is low in both mania and depression. L-tryptophan or 5-HT deficiency and changes in the light-dark cycle may result in reduced melatonin secretion from the pineal gland that disrupts the sleep-wake cycle, alters circadian rhythms, and causes seasonal affective changes. ... 

Another system that may contain a pacemaker is the avian pineal gland, which generates a circadian rhythm in melatonin the rhythm has also been observed in pineal cell cultures (see fig. 11.1) (Binkley, Riebman Reilly, 1978 Takahashi, Hamm Menaker, 1980 Takahashi et al., 1989). Melatonin is involved in the control of the sleep-wake cycle, and so analogues of the hormone are currently being developed for the prevention of jet lag. A circadian rhythm of activity has been demonstrated for the enzyme N-acetyltransferase, which catalyses an early step in melatonin synthesis (Binkley, 1983). 

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