The pineal gland and chronobiologic history: mind and spirit as feedsidewards in time structures for prehabilitation

Not only circadian rhythms — recurring patterns with a period of about 24 h (in the range of 20-28 h) — but also ultradian and infradian rhythms (with periods shorter than 20 h and longer than 28 h, respectively), characterize melatonin in humans, whether it is measured in blood, saliva, or urine. Among infradians, the about-yearly (circannual) and half-yearly (circasemiannual) components are noteworthy. At mid-latitude, circannuals may predominate in circulating melatonin during the daytime, whereas circasemiannuals may become more prominent during the nighttime. A stable half-yearly component also prominently characterizes the geomagnetic disturbance index Kp. Support for the hypothesis that Kp may influence human melatonin is provided by the fact that closer to tine pole, at 65 °N in Oulu, Finland, geomagnetic effects are stronger. There, circulating melatonin, measured around noon, exhibits a clear circasemiannual variation. Circaseptans and circasemiseptans, with periods of about a week and half a week, are found ubiquitously in relation to the pineal gland. In the case of melatonin secreted into the superfusion fluid by the pike pineal in vitro, kept at constant temperature in continuous darkness, the circaseptan component has an amplitude larger than that of the circadian rhythm. Circaseptans are also observed in the mouse pineal gland in vivo, wherein the presence of melatonin has been questioned, yet established by three independent groups of investigators who all documented a circadian variation peaking during the dark (rest) span. In vitro intermodulations among the pineal, pituitary, and adrenal glands were found to involve a rhythmically recurring and thus predictable sequence of opposite effects, i. e., a chronomodulation. Attenuation, no-effect, and amplification alternate circadian-dependently in the effect exerted by aqueous pineal extract or melatonin on the adrenal corticosterone response to pituitary incubation fluid or to an adrenocorticotropic hormone (ACTH) analog. This predictable sequence of effects is also seen for melatonin acting directly upon the adrenal gland. These results represent a challenge to those interested in integrative functions in health and in major diseases. Rather than remaining a confusing source of variability, the assessment of broad time structures (chronomes) yields new end points that can serve for treatment optimization by timing, and for risk assessment and management through the institution of preventive action as soon as risk elevation is detected. Several interdigitating and partly interwoven fields are centered around the pineal gland, where interactions between life and the cosmos may well lie. One of these fields concerns the rules of intermodulations among rhythms far beyond the circadian system. Another field consists of individuals’ adjustments and adaptations of species as features of the integration of organisms, as open systems with their ever-changing, predictable insofar as cyclic, environment, life has coded time structure in genes, but organisms still respond to remote drummers. The pineal gland may play a critical role as the window not only for photic and non-photic effects of the sun, but also for other galactic effects. Barriers to these fields exist only in the mind as deeply rooted conventions, such as homeostasis. The third field, chronobioethics, pertinent to pinealists’ concerns about the soul, whether they come from philosophy or molecular biology, is sketched only in a historical context here.