Circadian control

Hastings, J. W. (1987). Dinoflagellate bioluminescence biochemistry, cell biology, and circadian control. In Schoelmerich, J. (ed.), Biolumin. Chemilumin., Proc. Int. Biolumin. Chemilumin. Symp., 4th, 1986, pp. 343-350. Wiley, Chichester, UK. 

When compared with other monoamines, HA levels are low, with the highest levels seen in the hypothalamus and the lowest in the cerebellum. In addition, synthesis and release of HA is under circadian control. In rats, the average HA... 

Armstrong, S. M. (1989). Melatonin and circadian control in mammals. Experientia 45, 932-8. 

Hardin Whether they will cycle or not depends on whether aU of the proteins within the system are regulated at the post-transcriptional level. For example, if VRI is a major regulator of outputs in that phase of the cycle, if you remove VRI cycling and if the protein is dependent on the RNA, does that mean that all of the outputs subservient to VRI will then be arrhythmic This would require that VRI would also be under some sort of circadian control to preserve its downstream targets. 

The ultradian sleep—wake and temperature rhythm produced by 3rd ventricle infusion of TGFa closely resembles the effect of a focal excitotoxic lesion of SPZ neurons (Lu et al 2001). This ultradian rhythm is normally suppressed by circadian control and is disinhibited when SPZ neurons fail to relay SCN circadian information to sleep—wake circuits. Our results indicate that chronic TGFa administration uncouples SPZ neurons from sleep-regulatory circuits and that SPZ neurons expressing the EGFR transmit circadian information from the SCN to sleep—wake centres, in addition to likely regulating circadian locomotor activity. 

Weit That is more of a biology experiment. We are doing a screen of a lot of factors, and this would be unpractical in a screen. If the goal is to attempt to reconstitute circadian control of locomotor activity in a lesioned animal, I would want to wait until we had more information about which factors are involved. 

While the abundance of DBT does not oscillate, the subcellular localization of DBT does change throughout the circadian day (Fig. 2). In Drosophila, the subcellular distribution of DBT in the lateral neurons of the brain and in photoreceptor cells of the eye largely follows the changing localization of PER (Kloss et al 2001). In mammals, the pattern of CKl accumulation is also under circadian control the kinase appears to associate initially with mPER and mCRY in the cytoplasm, but it is also found in nuclear complexes and may regulate their movement to the nucleus (Lee et al 2001). 

As mentioned above, most of the preclinical studies on the effects of early stress have examined the impact of these experiences on adult animals. The preliminary work discussed in this section highlights the need for more developmentally focused preclinical studies of the effects of early stress. In addition, there is a need for more research on the development of the CC, and circadian control of cortisol secretion. 

The sleep-wake cycle is under the circadian control of oscillators and can be disrupted by misalignment between an individual s biological clock and external demands on the sleep cycle. Circadian rhythm sleep disorders usually present with either insomnia or hypersomnia, depending on the individual s performance requirements. Two commonly occurring circadian rhythm sleep disorders are jet lag and shift work sleep problems. 

Goergen EM, Bagay LA, Rehm K, Benton JL, Beltz BS (2002) Circadian control of neurogenesis. J Neurobiol 53 90-95... 

The mammalian suprachiasmatic nuclei contain an endogenous pacemaker that generates daily rhythms in behaviour and secretion of hormones. They stimulate evening ACTH secretion in the rat (Cascio etal. 1987). Kalsbeek etal. (1996) used microdialysis-mediated intracerebral administration of the vasopressin V,-receptor antagonist to study the mechanisms underlying the circadian control of basic corticosterone release in the rat. By timed administration of the vasopressin antagonist divided equally over the day/night cycle, they were able to uncover the existence of an additional stimulatory input from the suprachiasmatic nucleus to the hypothalamo-pituitary-adrenal axis. 

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