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Slow waves determine frequency and propagation characteristics of contractions in the small intestine, yet little is known about mechanisms of slow wave regulation. We propose a role for intracellular Ca(2+), inositol 1,4,5,-trisphosphate (IP(3))-sensitive Ca(2+) release, and sarcoplasmic reticulum (SR) Ca(2+) content in the regulation of slow wave frequency because 1) 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-AM, a cytosolic Ca(2+) chelator, reduced the frequency or abolished the slow waves; 2) thapsigargin and cyclopiazonic acid (CPA), inhibitors of SR Ca(2+)-ATPase, decreased slow wave frequency; 3) xestospongin C, a reversible, membrane-permeable blocker of IP(3)-induced Ca(2+) release, abolished slow wave activity; 4) caffeine and phospholipase C inhibitors (U-73122, neomycin, and 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate) inhibited slow wave frequency; 5) in the presence of CPA or thapsigargin, stimulation of IP(3) synthesis with carbachol, norepinephrine, or phenylephrine acting on alpha(1)-adrenoceptors initially increased slow wave frequency but thereafter increased the rate of frequency decline, 6) thimerosal, a sensitizing agent of IP(3) receptors increased slow wave frequency, and 7) ryanodine, a selective modulator of Ca(2+)-induced Ca(2+) release, had no effect on slow wave frequency. In summary, these data are consistent with a role of IP(3)-sensitive Ca(2+) release and the rate of SR Ca(2+) refilling in regulation of intestinal slow wave frequency.

PRC-063 significantly improved PERMP scores with an onset within 1 hr post-dose, and maintained improvement throughout the 16 hr post-dose study period compared with placebo in adults with ADHD.

Objective: To evaluate the efficacy and safety of a 16-hr multilayer-release methylphenidate (PRC-063) in a community-based adult ADHD population. Method: In a double-blind study, 375 participants were randomized to one of four fixed doses of PRC-063 or placebo. The primary outcome was the ADHD-Rating Scale-5 (RS). The first 50% of double-blind completers were invited to participate in a 6-month dose-optimized open-label study to assess response and safety. Results: In total, 333 participants completed the double-blind trial; 184 entered the open-label study. PRC-063 produced greater symptom reduction in ADHD-RS-5 total score from baseline compared with placebo in the double-blind study (least-square [LS] mean = −4.7 [−7.7, −1.6], p = .003). The most frequent adverse events were headache, insomnia, and decreased appetite. No significant sleep quality impact was observed ( p = .123). Significant improvements in ADHD-RS-5 scores from baseline continued through the open-label study ( p < .0001), coincident with dose optimization. Conclusion: PRC-063 was well tolerated and significantly improved ADHD symptomatology in adults.

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