While most laboratory rodents are active at night, many other species exhibit higher levels of activity during the daytime. The circadian system of diurnal species is not simply inverted relative to that of nocturnal species (Smale et al., 2003). While most rhythms peak at opposite phases in diurnal and nocturnal species, rhythmic melatonin production peaks at night in all species. Furthermore,...

The master circadian clock located in the suprachiasmatic nuclei (SCN) is dominantly entrained by external light/dark cycle to run with a period of a solar day, that is, 24 h, and synchronizes various peripheral clocks located in the body's cells and tissues accordingly. A daily restricted normocaloric feeding regime synchronizes the peripheral clocks but has no effect on SCN rhythmicity. The a...

This study was designed to determine whether the 24-h rhythms of clock gene expression and vascular smooth muscle (VSM) contractile responses are altered in type 2 diabetic db/db mice. Control and db/db mice were euthanized at 6-h intervals throughout the day. The aorta, mesenteric arteries, heart, kidney, and brain were isolated. Clock and target gene mRNA levels were determined by either real...

Melatonin-based photoperiod time-measurement and circannual rhythm generation are long-term time-keeping systems used to regulate seasonal cycles in physiology and behaviour in a wide range of mammals including man. We summarise recent evidence that temporal, melatonin-controlled expression of clock genes in specific calendar cells may provide a molecular mechanism for long-term timing. The agr...

Vertebrates have a central clock and also several peripheral clocks. Light responses might result from the integration of light signals by these clocks. The dermal melanophores of Xenopus laevis have a photoreceptor molecule denominated melanopsin (OPN4x). The mechanisms of the circadian clock involve positive and negative feedback. We hypothesize that these dermal melanophores also present per...

We develop a dynamical theory for the family of holomorphic correspondences Fa proved by current authors to be matings between modular group and parabolic rational maps in Milnor slice Per1(1) ([2]). Such mating endows complement limit set with geometry hyperbolic plane, equipped action group. introduce bi-infinite coding sequences geodesics this complement, utilising continued fraction express...