Sleep-wake regulatory

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. 

The best known is the circadian rhythm that determines the sleep-wake state and fluctuates during the day. There are, however, many other regulatory loops of whieh we are hardly aware (e.g., blood pressure, blood sugar level, respiration, ete). 

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