Dep. Biology, Bethany College, Bethany, WV 26031, USAInstitute of Systematics and Ecology of Animals, Russian Academy of Science, Siberian Branch, Frunze ul. 11, Novosibirsk 630091, Russia

Abstract

The multioscillatory principle of circadian organization of organism functions is based onthe ability of some organs and cells to generate independent set of oscillations with 24 hoursperiod. Coexistence of two or more independent rhythm producers provides a flexible structureof numerous cycles that take place in organism. The stable changes of circadian rhythms can becaused either by external factors (e.g. seasonal changes of photoperiod, socially determinedchanges of labour regime, cycles of sleep, feeding time) or by some inner factors, e.g. stresssyndrome or illness. In its turn the changes in phase relations between circadian rhythms ofsome hormones and neiromediators play an important role in formation of some adaptivereactions, i.e. seasonal changes in reproductive system, peculiarities of lipid metabolism, migration behaviour, preparation to hibernation, or the rate of metamorphism in amphibians.These data allow to formulate the hypothesis of temporal synergism. According to thishypothesis morphophysiological effect caused by joint action of two or more hormones orneiromediators is dependent on the phase relationships of their circadian rhythms.