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We have determined, by enzyme immunoassay, daily and circadian patterns of the concentrations of three peptides, which are located in the ventrolateral subdivision of the suprachiasmatic nucleus (SCN): vasoactive intestinal polypeptide (VIP), gastrin-releasing peptide (GRP), and neuropeptide Y (NPY). The contents of VIP and GRP, which are synthesized in the(More)
Circadian rhythms in drinking and running-wheel (locomotor) activity of rats with 6-hydroxydopamine (6-OHDA, 4 microg/2 microl per rat)-induced lesions in the ventral tegmental area (VTA) were examined under a light-dark (LD) cycle and constant dim light (5 lux). Under the LD cycle, the length of the locomotor activity period was decreased during the dark,(More)
The lycaenid butterfly, Niphanda fusca, has a parasitic relationship with its host ant, Camponotus japonicus: the caterpillars may use chemical mimicry to enter the ant nest where they are fed mouth-to-mouth by the adult ants until pupation. Nevertheless, larvae offer their host ants a nutritious secretion that contains 160 mM glucose and 43 mM glycine.(More)
To investigate the development of Arg-vasopressin (AVP) content and its diurnal rhythm in the suprachiasmatic nucleus (SCN), AVP was measured by enzyme immunoassay in the rat pup SCN punched out from tissue slices obtained at postnatal day (PD) 1, 5, 10, 12 and 20 from animals maintained under a light-dark cycle (LD). The AVP levels, measured at a(More)
Neural stem/progenitor cells (NPCs) reside in the subventricular zone (SVZ) and dentate gyrus in the adult mammalian brain. It has been reported that endogenous NPCs are activated after brain insults such as ischemic stroke. We investigated whether proliferation and migration of endogenous NPCs are increased after a collagenase-induced small intracerebral(More)
To investigate the developmental features of peptide levels in the suprachiasmatic nucleus (SCN), the contents of vasoactive intestinal polypeptide (VIP), gastrin-releasing peptide (GRP) and Arg-vasopressin (AVP) were measured in punched-out SCN tissue from rat pups on postnatal days (PD) 4, 15 and 20 using a specific enzyme immunoassay. The VIP content was(More)
Twenty-four hour patterns in somatostatin (SS)-like immunoreactivity (LI) within the suprachiasmatic nucleus (SCN) were determined by enzyme immunoassay in rats blinded by bilateral orbital enucleation or kept sighted under light-dark conditions. A remarkable circadian rhythm was found in the concentration of SS-LI in the SCN under blinded conditions. The(More)
Metabolic activity in the suprachiasmatic nucleus (SCN), a center of biological rhythm, is higher during the daytime than at night. The rhythmic oscillation in the SCN is feedback controlled by the Clock/Bmal1 heterodimer binding to the E-box in target genes (e.g., Arg-vasopressin). Similar transcriptional regulation by Npas2/Bmal1 heterodimer formation(More)
Melatonin, which is released from the pineal gland, influences many physiological events concerned with circadian rhythm. Body temperature levels and rhythmicity are tightly coupled with locomotor activity. To understand the functions of melatonin, we determined the effects of melatonin injection on locomotor activity measured by running-wheel activity and(More)
To examine the roles of Arg-vasopressin (AVP)- and vasoactive intestinal peptide (VIP)-containing neurons in the suprachiasmatic nucleus (SCN) in production of circadian rhythmicity of locomotor activity, variations in the contents of AVP and VIP in punched-out SCN tissue and locomotor activity were measured under a light-dark cycle as well as under(More)