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Mammalian circadian clocks consist of complex integrated feedback loops that cannot be elucidated without comprehensive measurement of system dynamics and determination of network structures. To dissect such a complicated system, we took a systems-biological approach based on genomic, molecular and cell biological techniques. We profiled suprachiasmatic(More)
The suprachiasmatic nucleus (SCN) is the neuroanatomical locus of the mammalian circadian pacemaker. Here we demonstrate that an abrupt shift in the light/dark (LD) cycle disrupts the synchronous oscillation of circadian components in the rat SCN. The phases of the RNA cycles of the period genes Per1 and Per2 and the cryptochrome gene Cry1 shifted rapidly(More)
Pinopsin is a blue-sensitive photoreceptive molecule possibly involved in photic entrainment of the circadian pacemaker in the chicken pineal gland. To characterize pinopsin as a circadian photoreceptor, antibodies were raised against the C-terminal portion of pinopsin. As expected from the divergence of the amino acid sequence of this region, the resultant(More)
In order to study the mechanisms of ocular circadian rhythms in the pigeon, we measured melatonin and dopamine simultaneously from the eye using in vivo microdialysis. In experiment 1, the phase relationship between circadian rhythms of ocular melatonin and dopamine under light-dark cycles (LD) and continuous dim light (LLdim) was examined. Under LD,(More)
We detected rhodopsin gene expression in the pigeon lateral septum, a photosensitive deep brain region that is responsible for the photoperiodic gonadal response. The nucleotide sequence of the deep brain rhodopsin cDNA clone exactly matched that of the retinal one, indicating that a single rhodopsin gene is transcribed in the two tissues.(More)
Photic resetting of a biological clock is one of the fundamental characteristics of circadian systems and allows living organisms to adjust to a particular environment. Nocturnal light induces the Per1 and Per2 genes, which leads to a resetting of the circadian clock in the suprachiasmatic nucleus (SCN), the mammalian circadian center. In our present study,(More)
Vasoactive intestinal peptide (VIP)-like immunoreactive terminal fields were examined in the lateral septum of the pigeon by means of immunocytochemistry. According to light-microscopic observations, these projections originated from VIP-like immunoreactive cerebrospinal fluid (CSF)-contacting neurons, which are located in the ependymal layer of the lateral(More)
Our previous study has shown that the phases of circadian rhythms of ocular melatonin and dopamine are always opposite and intraocular melatonin injection suppresses dopamine release. Therefore, it is possible that dopamine rhythms result from inhibitory action of melatonin. We have examined this possibility in the following experiments. In the first(More)
Ocular melatonin rhythms were measured in pigeons (Columba livia) by in vivo microdialysis. The birds were placed in light-dark cycles with 12 h of light and 12 h of darkness (LD12:12) or continuous dim light (LLdim) after LD12:12. Under LD12:12, melatonin levels were low during the light and high during the dark. The rhythms persisted under LLdim with(More)
Kisspeptin/metastin has been implicated as a critical regulator in luteinizing hormone (LH) secretion and the reproductive system mediating the effect of estrogen on GnRH neurons. In the present study we examined the sex differences in the effects of estrogen on Kiss1/kisspeptin expression in the forebrain by using gonadectomized rats to assess the(More)