抄録
The mammalian circadian clock governs daily rhythms of physiological function including sleep, activity, energy metabolism, and circulation. Genetic approaches to elucidate the circadian clock have revealed the core mechanism of the molecular clock that generates the circadian rhythm at both molecular and cellular levels. Recent studies indicate that cardiovascular function such as the regulation of blood pressure and heart rate is under the control of the molecular clock. However, little is known about how the molecular clock transmits the circadian signal to the regulatory mechanism of circulation to produce the cardiovascular circadian rhythm at the organismal level. Here we show that prokineticin 2, a downstream molecule of the molecular clock, regulates cardiovascular function in rats. Both prokineticin 2 and its specific receptor were abundant in the nucleus tractus solitarius, a core central target that regulates cardiovascular function. Interestingly, microinjection of prokineticin 2 into the nucleus tractus solitarius of rats decreased blood pressure and heart rate predominantly during the light period when rodents normally sleep. Our results suggest that prokineticin 2 may play an important role in the generation of the circadian rhythm in circulation. [J Physiol Sci. 2008;58 Suppl:S95]
