THE INTERNAL COORDINATION OF CIRCADIAN-RHYTHMS AND TEMPORAL SYNERGISMIN ADAPTIVE REACTIONS OF ANIMALS

The multioscillatory principle of circadian organization of organism f unctions is based on the ability of some organs and cells to generate independent set of oscillations with 24 hours period. Coexistence of t wo or more independent rhythm producers provides a flexible structure of numerous cycles that take place in organism. The stable changes of circadian rhythms can be caused either by external factors (e.g. seaso nal changes of photoperiod, socially determined changes of labour regi me, cycles of sleep, feeding time) or by some inner factors, e.g. stre ss syndrome or illness. In its turn the changes in phase relations bet ween circadian rhythms of some hormones and neiromediators play an imp ortant role in formation of some adaptive reactions, i.e. seasonal cha nges in reproductive system, peculiarities of lipid metabolism, migrat ion behaviour, preparation to hibernation, or the rate of metamorphism in amphibians. These data allow to formulate the hypothesis of tempor al synergism. According to this hypothesis morphophysiological effect caused by joint action of two or more hormones or neiromediators is de pendent on the phase relationships of their circadian rhythms.