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Bone marrow mesenchymal stem cells (MSCs) are a promising cell source for regenerative medicine; however, their cellular physiology is not fully understood. The present study aimed at exploring the potential roles of the two dominant functional ion channels, intermediate-conductance [Ca.sup.2+]-activated potassium ([IK.sub.Ca]) and volume-sensitive chloride ([I.sub.Cl.vol]) channels, in regulating proliferation of mouse MSCs. We found that inhibition of [IK.sub.Ca] with clotrimazole and [I.sub.Cl.vol] with 5-nitro-1-(3-phenylpropylamino) benzoic acid (NPPB) reduced cell proliferation in a concentration-dependent manner. Knockdown of KCa3.1 or Clcn3 with specific short interference (si)RNAs significantly reduced [IK.sub.Ca] or [I.sub.cl.vol] density and channel protein and produced a remarkable suppression of cell proliferation (by 24.4 [+ or -] 9.6% and 29.5 [+ or -] 7.2%, respectively, P < 0.05 vs. controls). Flow cytometry analysis showed that mouse MSCs retained at [G.sub.0]/[G.sub.1] phase (control: 51.65 [+ or -] 3.43%) by inhibiting [[K.sub.Ca] or [I.sub.Cl.vol] using clotrimazole (2 [micro]M: 64.45 [+ or -] 2.20%, P < 0.05) or NPPB (200 [micro]M: 82.89 [+ or -] 2.49%, P < 0.05) or the specific siRNAs, meanwhile distribution of cells in S phase was decreased. Western blot analysis revealed a reduced expression of the cell cycle regulatory proteins cyclin D1 and cyclin E. Collectively, our results have demonstrated that [IK.sub.Ca] and [I.sub.Cl.vol] channels regulate cell cycle progression and proliferation of mouse MSCs by modulating cyclin D1 and cyclin E expression. intermediate conductance [Ca.sub.2+]-activated [K.sup.+] current; volume sensitive [Cl.sup.-] current; cell cycle progression; short interference RNA

Autoregulation of renal blood flow (RBF) occurs via myogenic and tubuloglomerular feedback (TGF) mechanisms that are engaged by pressure changes within preglomerular arteries and by tubular flow and content, respectively. Our understanding of autoregulatory function in the kidney largely stems from experiments in anesthetized animals where renal perfusion pressure is precisely controlled. However, normally occurring variations in blood pressure are sufficient to engage both myogenic and TGF mechanisms, making the assessment of autoregulatory function in conscious animals of significant value. To our knowledge, no studies have evaluated the dynamics of RBF in conscious mice. Therefore, we used spectral analysis of blood pressure and RBF and identified dynamic operational characteristics of the myogenic and TGF mechanisms in conscious, freely moving mice instrumented with ultrasound flow probes and arterial catheters. The myogenic response generates a distinct resonance peak in transfer gain at 0.31 [+ or -] 0.01 Hz. Myogenic-dependent attenuation of RBF oscillations, indicative of active autoregulation, is apparent as a trough in gain below 0.3 Hz (-6.5 [+ or -] 1.3 dB) and a strong positive phase peak (93 [+ or -] 9 deg), which are abolished by amlodipine infusion. Operation of TGF produces a local maximum in gain at 0.05 [+ or -] 0.01 Hz and a positive phase peak (62.3 [+ or -] 12.3 deg), both of which are eliminated by infusion of furosemide. Administration of amlodipine eliminated both myogenic and TGF signature peaks, whereas furosemide shifted the myogenic phase peak to a slower operational frequency. These data indicate that myogenic and TGF dynamics may be used to investigate the effectiveness of renal autoregulatory mechanisms in conscious mice. myogenic; tubuloglomerular feedback; mouse; renal blood flow; dynamics; conscious

Mild physical activity performed immediately after a bout of intense exercise in fasting humans results in net glycogen breakdown in their slow oxidative (SO) muscle fibers and glycogen repletion in their fast twitch (FT) fibers. Because several animal species carry a low proportion of SO fibers, it is unclear whether they can also replenish glycogen in their FT fibers under these conditions. Given that most skeletal muscles in rats are poor in SO fibers ( glycogen synthesis; regulation; carbohydrate; sprint; and exercise

This article discusses circadian rhythms in fruit fly Drosophila. The data reveal that the circadian clock is composed of multiple feedback loops within the circadian oscillator and involvement of proteins in transmitting environmental cues.