Circadian clocks are the endogenous oscillators that harmonize a variety of physiological processes within the body. Although many urinary functions exhibit clear daily or circadian variation in diurnal humans and nocturnal rodents, the precise mechanisms of these variations are as yet unclear. In the present study, we demonstrate that Per2 promoter activity clearly oscillates in neonate and adult bladders cultured ex vivo from Per2::Luc knock-in mice. In subsequent experiments, we show that multiple local oscillators are operating in all the bladder tissues (detrusor, sphincter and urothelim) and the lumbar spinal cord (L4-5) but not in the pontine micturition center or the ventrolateral periaqueductal gray of the brain. Accordingly, the water intake and urine volume exhibited daily and circadian variations in young adult wild-type mice but not in Per1-/- Per2-/- mice, suggesting a functional clock-dependent nature of the micturition rhythm. Particularly in PDK mice, the water intake and urinary excretion displayed an arrhythmic pattern under constant darkness, and the amount of water consumed and excreted significantly increased compared with those of WT mice. These results suggest that local circadian clocks reside in three types of bladder tissue and the lumbar spinal cord and may have important roles in the circadian control of micturition function.
Animals ; *Circadian Clocks ; Drinking ; Mice ; Organ Specificity ; Periaqueductal Gray/metabolism/physiology ; Period Circadian Proteins/genetics/*metabolism ; Pons/metabolism/physiology ; Spinal Cord/*metabolism/physiology ; Urinary Bladder/innervation/metabolism/*physiology ; Urination

The calbindin D-28k (CB)-containing neurons in the interstitial nucleus of the spinal trigeminal tract (INV) that receive visceral and orofacial somatic nociceptive information and emanate projections to the parabrachial nuclei (PB) were investigated by the triple-labeled methods of fluorogold (FG) retrograde tracing combined with Fos and CB proteins immunofluorescence histochemistry in the rat. The results showed (1) in the perioral stimulation group, a large number of FG-retrograde labeled and Fos-immunoreactive neurons were found in the paratrigeminal nucleus (PaV) and the dorsal paramarginal nucleus (PaMd) of the INV ipsilateral to FG and formalin injection made to the PB and lips, respectively, while a lot of CB-immunoreactive neurons were distributed in the INV bilaterally; (2) a majority of the FG-retrograde labeled neurons (77.3%) were double-labeled with CB, and 40.7% of them were double-labeled with Fos; about 38.5% of FG/CB double-labeled neurons were FG/CB/Fos triple-labeled in the INV; and (3) in the upper alimentary tract stimulation group, the distribution and the numbers of FG-retrograde labeled, CB-immunoreactive neurons and FG/CB double-labeled neurons in the INV were similar to those of the perioral stimulation group as described above, except that the Fos immunoreactive neurons were distributed in the INV bilaterally, approximately 41.9% of the FG-retrograde labeled neurons were FG/Fos double-labeled, and over half (52.0%) of those double-labeled neurons were FG/CB/Fos triple-labeled. The results indicate that a part of CB-containing neurons in the INV receive orofacial somatic and visceral nociceptive information and that these neurons sent projections directly to the PB. The CB-containing neurons might play an important role in the transmission of the peripheral nociceptive information from INV to PB.
Animals ; Calbindins ; Face ; innervation ; Male ; Medulla Oblongata ; physiology ; Nerve Tissue Proteins ; metabolism ; Neural Pathways ; physiology ; Neurons ; metabolism ; physiology ; Nociceptors ; physiology ; Pain ; metabolism ; physiopathology ; Pons ; physiology ; Rats ; Rats, Sprague-Dawley ; S100 Calcium Binding Protein G ; metabolism ; Trigeminal Nucleus, Spinal ; physiology ; Viscera ; innervation

OBJECTIVEIt has been known that glial line-cell derived neurotrophic factor (GDNF) has the nutritional and protective effect in motor neurons. In this experiment, we investigated the character of GDNF mRNA expression in a facial nerve-striking model; combined with other scholars' experimental results; and analyzed what role GDNF plays in the regeneration process of injured motor nerves.

METHODSWe established a striking model in rabbit facial nerves with a striking gun with the striking velocity of 10 m/s and the total striking energy of 7.5 J. Then we detected the GDNF mRNA expression in facial neurons and axons with in situ hybridization on days 3, 7, 14 and 21 after striking. We counted the expression numbers of facial neurons and, compared with normal facial neurons and peripheral facial nerves.

RESULTSWe detected GDNF mRNA expression in the facial neurons from day 3 to day 21 after the facial nerve injured by striking. The peak of GDNF mRNA expression appeared on the 7th day, and then the expression number of facial neurons decreased gradually. A high level expression was also detected on day 21. GDNF mRNA expression was not detected neither in Schwann cells nor in normal facial neurons from the 3rd day to the 21st day.

CONCLUSIONGDNF is a kind of neurotrophic growing factor (NGF) that could be activated by injury. The character of GDNF mRNA expression was accordant to the process of nerve regeneration. These results showed that GDNF plays a very important role in the regeneration of injured motor nerves.

Animals ; Facial Nerve ; metabolism ; Facial Nerve Injuries ; metabolism ; Glial Cell Line-Derived Neurotrophic Factor ; In Situ Hybridization ; Male ; Motor Cortex ; metabolism ; physiology ; Nerve Growth Factors ; biosynthesis ; genetics ; Nerve Regeneration ; Neuronal Plasticity ; physiology ; Neurons ; metabolism ; Pons ; cytology ; metabolism ; physiology ; RNA, Messenger ; biosynthesis ; genetics ; Rabbits