Browsing by Subject "Phosphodiesterase"

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    A way to increase the bioaccesibility and photostability of roflumilast, a COPD treatment, by cyclodextrin monomers
    (MDPI, 2019-04-30) Matencio, Adrián; Hernández García, Samanta; García Carmona, Francisco; López Nicolás, José Manuel; Bioquímica y Biología Molecular A
    Roflumilast is an orally available inhibitor of phosphodiesterase (PDE) type 4, which is widely used in chronic obstructive pulmonary diseases. However, it has low solubility and adverse effects include diarrhea and nausea. Since its solubilization may improve treatment and, dismissing any adverse effects, its interaction with cyclodextrins (CDs) was studied. The Higuchi-Connors method was used to determine the complexation constant with different CDs, pH values and temperatures. Molecular docking was used to predict interaction between the complexes. An in vitro digestion experiment was carried out to test roflumilast protection. Finally, the photostability of the complex was evaluated. The complex formed with β-CD had the highest K11 value (646 ± 34 M−1), although this value decreased with increasing temperature. Similarly, K11 decreased as the pH increased. In vitro digestion showed that CDs protect the drug during digestion and even improve its bioaccessibility. Finally, CDs reduced the drug’s extreme photosensitivity, originating a fluorescence signal, which is described for first time. The kinetic parameters of the reaction were obtained. This study not only completes the complexation study of roflumilast-CD, but also points to the need to protect roflumilast from light, suggesting that tablets containing the drug might be reformulated.
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    In situ detection of cyclic AMP-phosphodiesterase activity in the heart of Lewis and Sprague-Dawley rats: the effect of restraint stress or amphetamine application
    (Murcia : F. Hernández, 2004) Okruhlicová, L.; Klenerová, V.; Hynie, S.; Sída, P.
    Cyclic AMP plays an important role in heart functions under normal as well as pathological conditions. Since phosphodiesterase (PDE), responsible for the hydrolysis of cAMP, is equally important as synthesizing adenylyl cyclase, we decided to determine its activity by cytochemical procedure after exposure of rats to restraint stress or an acute dose of amphetamine. Sprague-Dawley (S-D) and Lewis (LE) rats, the latter known to have a deficient hypothalamo-pituitary-adrenal axis activity, were used in order to disclose the possible significance of rat strain on PDE activity. Animals were divided into 3 groups: controls, rats treated with an acute dose of amphetamine (8 mg/kg, i.p., for 60 min) and rats under restraint stress for 60 min. Control hearts of both strains revealed PDE activity on sarcolemma of cardiomyocytes and plasmalemma of endothelial cells of microvessels. In LE rats we observed an additional enzyme reaction in junctional sarcoplasmic reticulum. In addition, cardiomyocytes of LE rats revealed a higher PDE activity when compared to S-D rats. Restraint stress decreased PDE activity in cardiomyocytes of LE rats while amphetamine markedly inhibited enzyme activity in cardiomyocytes of S-D rats. Endothelial PDE was more resistant to stress. Our results indicate differences in PDE localization and variations in sensitivity of myocardial cAMP-PDE of LE and S-D rat strains to restraint stress and amphetamine application
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    Naris occlusion alters transductory protein immunoreactivity in olfactory epithelium
    (Murcia : F. Hernández, 2006) Coppola, D.M.; Waguespack, A.M.; Reems, M.R.; Butman, M.L.; Cherry, J.A.
    We have recently shown that unilateral naris occlusion (UNO) causes an increase in olfactory marker protein (OMP) immunoreactivity (IR) in mouse olfactory sensory neurons (OSN) from the occluded side of the nasal cavity and a decrease in OMP-IR on the non-occluded side, relative to controls. Given OMP's demonstrated role in olfactory modulation, these OMPIR changes have been interpreted as a compensatory response by OSNs to odor deprivation on the occluded side and to supernormal exposure to odor on the nonoccluded side of the nasal cavity. In the current study, we examined the developmental timing and the regional distribution of this process throughout the nasal cavity using immunocytochemistry. Results demonstrate that OMP-IR diverges in OSNs from the occluded side relative to the non-occluded side of the nasal cavity within eleven days after UNO, with statistically significant differences measurable after 17 days (n=16). We also measured relative levels of the Type 4 phosphodiesterase (PDE4A), another potential olfactory modulator, in nasal cavity tissue from UNO (n=8) and untreated mice (n=9) using western blots and immunocytochemistry. Like OMP, PDE4A-IR increased on the occluded side of the nasal cavity after UNO. Finally, we used immunocytochemistry to assess relative levels of olfactory-specific adenylyl cyclase (ACIII, n=4) and G-protein (Golf, n=2) in OSNs from the occluded and non-occluded sides of the nasal cavity of UNO mice. Following UNO, ACIII but not Golf -IR levels diverged comparing the occluded to the non-occluded sides of the nasal cavity. Taken together, our findings provide support for the previously unknown phenomenon of compensatory responses by OSNs to odor environment.