Systematic Analysis of Biological Timing

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In the systematic analysis of biological timing, the following results were obtained.1)Mollecular mechanisms of subcellular oscillation :cClock genes were analyzed in two different speices, frq gene in Neurospora (Nakashima), and per and timeless genes in Drosophila (Young). From the dynamics of gene products, a closed feedback loop of transcription-translation-protein systhesis-transcriptional regulation was suggested to be involved in the circadian rhythm generation.2)Mechanisms of entrainment and oscillatory couplingNeuroendcrinological studies revealed that the serotonergic system was involved in the oscillatory coupling of pacemakers located in the optic lobes of cricket (Tomioka) and in the circadian rhythm of VIPmRNA in the rat SCN (Inouye). Mutagen-induced transgenic mice were established which showed abnormal rhythmicity under constant conditions (Takahashi). Neuronal activity was monitored from a single SCN neuron cultured on electrodes (Block).3)Mechanism of circadian rhythm expression Circadian clock of congenital rod deficient mice is still capable of entraining to light (Ebihara). The roles of pineal gland and retina were investigated in the circadian organization of Japanese newts (Aoki). Involvement of NO was demonstrated in the NMDA receptor mediated phase-shift of SCN neuronal activity rhythm in rats (Shibata). Paraventricular NPY release was essential for the prefeeding corticosterone peak in rats under periodie feeding (S.Honma). Social entrainment of human circadian rhythm was demonstrated under dim light condition (K.Honma). Light-induced fos gene expression was not necessarily associated with phase-shift of the circadian rhythm (Abe). A most prominent property of the tau-mutant hamster was in the weakened oscillatory coupling (Menaker). GnRH pulsatile secretion regulated the transcription of LHbeta subunit (Thorner). Involvement of serotonergic system was demonstrated in the exercise-induced phase-shift in hamsters (Turek)