Pineal

The accuracy of a molecular mechanics or seim-eni pineal quantum mechanics method depends on the database used to parameterize the method. This is true for the type of molecules and the physical and chemical data in the database. Frequently, these methods give the best results for a limited class of molecules or phen omen a. A disad van tage of these methods is that you m u si have parameters available before running a calculation. Developing param eiers is time-consuming. 

The following data ( fable 1) for niolcctilcs, including hydrocarbon s, strained ring system s. molecn les with heieroatom s, radicals, and ions conies from a review by Stewart. For most organic molecules,, YM 1 reports heals of formation accurate to within a few kilocalories per rn ol. bor soni e molecules (particularly inorgari ic compoun ds wdth several halogens, such as perch loryl fluoride, even the best sem i-em pineal method fails completely. 

As with the other sem i-cm pineal methods. HyperGhem s im p le-meiitation of ZINDO/1 is restricted to spin multiplicities up to a quartet state. ZIXDO/1 lets you calculate the energy slates in molecules containing transition metals. 

A hormone synthesized in the pineal gland Certain mental disorders are be lieved to be related to sero tonin levels in the brain )... 

Melatonin. Melatonin (A/-acetyl-5-metlioxytryptaniine) [73-31-4] C 2H gN2O2(250) is secreted from the pineal gland and retina during dark periods of the vertebrate circadian rhythm (65). Melatonin regulates biological rhythms and neuroendocrine function and is formed from serotonin (5-HT). 

Evidence has been put forward that 6-methoxy-l-methyl-l,2,3,4-tetrahydro-j3-carboline may be a component of animal tissues and may be identical with adrenoglomerulotrophine, a factor controlling aldosterone secretion, which is found in the pineal gland where it occurs together with 5-hydroxytryptamine... 

Zipfel, m, tip, point, end, summit lobe, ear, Zirbel-. (Anat.) pineal, -drtise, /. pineal gland, pineal body, -ficlite, -kiefer, /, Swiss pine (Pinua cembra). -nuBB, /. cedar nut (from Pinua cembra). zirka, adv. about, approximately. zifkaBBisch, a. Circassian. 

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... 

Neurons within the SCN innervate those hypothalamic areas which have a crucial role in the regulation of the reproductive cycle, mood and sleep/arousal, as well as regions such as the basal forebrain and the thalamus which help to determine the state of arousal. They also project to the pineal gland to govern the synthesis and release of... 

Figure 22.1 Pathways projecting to and from the suprachiasmatic nucleus (SCN). Inputs from photoreceptors in the retina help to reset the circadian clock in response to changes in the light cycle. Other inputs derive from the lateral geniculate complex and the serotonergic, Raphe nuclei and help to reset the SCN in response to non-photic stimuli. Neurons in the SCN project to the hypothalamus, which has a key role in the regulation of the reproductive cycle, mood and the sleep-waking cycle. These neurons also project to the pineal gland which shows rhythmic changes in the rate of synthesis and release of the hormone, melatonin...

Figure 22.3 Possible links in the induction of circadian rhythm between daylight, the suprachiasmatic nucleus and melatonin release from the pineal gland. Some fibres in the optic nerve, projecting from the eye to the lateral geniculate nucleus (LGN) in the thalamus, innervate the suprachiasmatic nucleus (SCN) in the anterior hypothalamus, via the retinohypothalamic tract (RHT). Others project to the SCN from the LGN in the geniculohypothalamic tract (GHT). The release of melatonin into the circulation from the pineal gland (PG) is maximal at night and appears to be controlled partly by noradrenaline released from sympathetic nerves originating in the superior cervical ganglion (SCG). Melatonin receptors are found in the SCN, the removal of which dampens melatonin secretion...

Senior Researcher, Department ofChemical Sensors, Karpov Institute of Pineal Chemistry, Moscov, Russia. 

Sanchez-Barcelo E., Mediavilla M.D., Sanchez-Criado J.E., Cos S., et al. (1985). Anti-gonadal actions of olfaction and light deprivation effects of blindness and main olfactory bulb — deafferentation and transection of vomeronasal nerve or bulbectomy. J Pineal Res 2, 177-190. 

Castaneda T., de Prado B., Prieto D., Mora F. (2004). Circadian rhythms of dopamine, glutamate and GABA in the striatum and nucleus accumbens of the awake rat modulation by light. J. Pineal Res. 36, 177-85. 

The circadian pattern of pineal NAT activity and consequently melatonin secretion is controlled by the suprachiasmatic nuclei (SCN) as it is abolished by lesions of the SCN, the major circadian oscillator (Klein and Moore 1979). Thus, the environmental L/D cycle acts as the pervasive and pre-eminent Zeitgeber that regulates melatonin synthesis (Scheer and Czeisler 2005). 

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