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Spontaneous electrical pacemaker activity occurs in tunica muscularis of the gastrointestinal tract and drives phasic contractions. Interstitial cells of Cajal (ICC) are the pacemaker cells that generate and propagate electrical slow waves. We used Ca2+ imaging to visualize spontaneous rhythmicity in ICC in the myenteric region (ICC-MY) of the murine small intestine. ICC-MY, verified by colabeling with Kit antibody, displayed regular Ca2+ transients that occurred after electrical slow waves. ICC-MY formed networks, and Ca2+ transient wave fronts propagated through the ICC-MY networks at ∼2 mm/s and activated attached longitudinal muscle fibers. Nicardipine blocked Ca2+ transients in LM but had no visible effect on the transients in ICC-MY. ß-Glycynhetinic acid reduced the coherence of propagation, causing single cells to pace independently. Thus, virtually all ICC-MYs are spontaneously active, but normal activity is organized into propagating wave fronts. Inhibitors of dihydropyridine-resistant Ca2+ entry (Ni2+ and mibefradil) and elevated external K+ reduced the coherence and velocity of propagation, eventually blocking all activity. The mitochondrial uncouplers, FCCP, and antimycin and the inositol 1,4,5-trisphosphate receptor-inhibitory drug, 2-aminoethoxydiphenyl borate, abolished rhythmic Ca2+ transients in ICC-MY. These data show that global Ca2+ transients in ICC-MYs are a reporter of electrical slow waves in gastrointestinal muscles. Imaging of ICC networks provides a unique multicellular view of pacemaker activity. The activity of ICC-MY is driven by intracellular Ca2+ handling mechanisms and entrained by voltage-dependent Ca2+ entry and coupling of cells via gap junctions. [ABSTRACT FROM AUTHOR]

Steamed and freeze-dried mature silkworm powder (SMSP) is a natural food containing a large amount of various functional materials and has various health promoting effects. SMSP is known to increase the life expectancy and healthspan, simultaneously. The accomplishment of extension of healthspan should be possible to achieve by activating various signaling pathways delaying aging in various tissues, not by regulating only a few signaling pathways. Consistent with this notion, SMSP increased the resistant to Parkinson disease by enhancing olfaction and mitochondrial activity in neurons of animal models. In addition, SMSP could enhance the gastrointestinal functions. The animals consumed SMSP showed enhanced alcohol metabolisms, reduced cholesterols in bloods, increased resistance to carcinogens causing liver cancers, and protective effects in alcohol induced stomach ulcers. Furthermore, SMSP was also effective in appearance. The SMSP consumed animals showed reduced skin pigmentations and more hair growth compared with control animals. Taken together, the functional enhancement effects of SMSPs in various tissues and organs, which have been discovered to date, are combined to extend healthspan. Therefore, SMSP can be regarded as calorie restriction mimetics. Further studies in the health promoting effects of SMSP will contribute to identifying new applicable diseases, resulted in increased sales of SMSP and incomes of sericulture farmers. [ABSTRACT FROM AUTHOR]

Recently matured silkworm powder was developed by RDA. In this study, the effect of pulverizing method on the particle size of matured silkworm powder was examined. FESEM was performed to observe the morphology and to measure the particle size of silkworm powder. Particle morphology of air-jet mill pulverized powder was round and smooth, however, those of roller-mill and hammer-mill pulverized mature silkworm was more harsh and square. Particle size was varied with pulverizing technique as follows; 1.1 μm (air-jet mill), 10 μm (roller mill), and 120 μm (hammer mill), respectively. A proximate analysis results of air-jet mill powder showed that crude protein, crude lipid, crude fiber, and ash was 73%, 12%, 1.95%, and 3.4%, respectively. According to our results, air-jet mell technique might be used to make a tiny matured silkworm powder. [ABSTRACT FROM AUTHOR]