Protective effects of exogenous and endogenous hydrogen sulfide in mast cell-mediated pruritus and cutaneous acute inflammation in mice.

Published onlineJournal ArticleThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.The recently described 'gasomediator' hydrogen sulfide (H2S) has been involved in pain mechanisms, but its effect on pruritus, a sensory modality that similarly to pain acts as a protective mechanism, is poorly known and controversial. The effects of the slow-releasing (GYY4137) and spontaneous H2S donors (Na2S and Lawesson's reagent, LR) were evaluated in histamine and compound 48/80 (C48/80)-dependent dorsal skin pruritus and inflammation in male BALB/c mice. Animals were intradermally (i.d.) injected with C48/80 (3μg/site) or histamine (1μmol/site) alone or co-injected with Na2S, LR or GYY4137 (within the 0.3-100nmol range). The involvement of endogenous H2S and KATP channel-dependent mechanism were also evaluated. Pruritus was assessed by the number of scratching bouts, whilst skin inflammation was evaluated by the extravascular accumulation of intravenously injected (125)I-albumin (plasma extravasation) and myeloperoxidase (MPO) activity (neutrophil recruitment). Histamine or C48/80 significantly evoked itching behavior paralleled by plasma extravasation and increased MPO activity. Na2S and LR significantly ameliorated histamine or C48/80-induced pruritus and inflammation, although these effects were less pronounced or absent with GYY4137. Inhibition of endogenous H2S synthesis exacerbated C48/80-induced responses, whereas the blockade of KATP channels by glibenclamide did not. High-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) revealed that Na2S and LR, but not GYY4137, significantly attenuated C48/80-induced histamine release from rat peritoneal mast cell in vitro. We provide first evidences that H2S exerted protective effect against acute pruritus mediated via histaminergic pathways in murine skin, thus making of H2S donors a potential alternative/complementary therapy for treatment of acute pruritus.Sao Paulo Research Foundation (Fapesp grant numbers: 2013/04.151-3, 2014/15.576-8, 2014/24.518-1) and CNPq (grant number: 163278/2012-1). GDN, MNM and SKPC are recipients of fellowships from the National Council for Scientific and Technological Development (CNPq). We thank Irene M Gouvea, Flávia B de Lira and Mauro Sucupira for their techinical support

Hydrogen sulfide donors alleviate itch secondary to the activation of type-2 protease activated receptors (PAR-2) in mice.

Published onlineJOURNAL ARTICLEHydrogen sulfide (H2S) has been highlighted as an endogenous signaling molecule and we have previously found that it can inhibit histamine-mediated itching. Pruritus is the most common symptom of cutaneous diseases and anti-histamines are the usual treatment; however, anti-histamine-resistant pruritus is common in some clinical settings. In this way, the involvement of mediators other than histamine in the context of pruritus requires new therapeutic targets. Considering that the activation of proteinase-activated receptor 2 (PAR-2) is involved in pruritus both in rodents and humans, in this study we investigated the effect of H2S donors on the acute scratching behavior mediated by PAR-2 activation in mice, as well as some of the possible pharmacological mechanisms involved. The intradermal injection of the PAR-2 peptide agonist SLIGRL-NH2 (8-80nmol) caused a dose-dependent scratching that was unaffected by intraperitoneal pre-treatment with the histamine H1 antagonist pyrilamine (30mg/kg). Co-injection of SLIGRL-NH2 (40nmol) with either the slow-release H2S donor GYY4137 (1 and 3nmol) or the spontaneous donor NaHS (1 and 0.3nmol) significantly reduced pruritus. Co-treatment with the KATP channel blocker glibenclamide (200nmol) or the nitric oxide (NO) donor sodium nitroprusside (10nmol) abolished the antipruritic effects of NaHS; however, the specific soluble guanylyl cyclase inhibitor ODQ (30μg) had no significant effects. The transient receptor potential ankyrin type 1 (TRPA1) antagonist HC-030031 (20μg) significantly reduced SLIGRL-NH2-induced pruritus; however pruritus induced by the TRPA1 agonist AITC (1000nmol) was unaffected by NaHS. Based on these data, we conclude that pruritus secondary to PAR-2 activation can be reduced by H2S, which acts through KATP channel opening and involves NO in a cyclic guanosine monophosphate (cGMP)-independent manner. Furthermore, TRPA1 receptors mediate the pruritus induced by activation of PAR-2, but H2S does not interfere with this pathway. These results provide additional support for the development of new therapeutical alternatives, mainly intended for treatment of pruritus in patients unresponsive to anti-histamines.MNM and SKPC are recipients of fellowships from the National Council for Scientific and Technological Development (CNPq) and grants from the Sao Paulo Research Foundation (FAPESP). RT, MW and MEW would like to thank the Brian Ridge Scholarship for its support (RT)

Vasorelaxant Activity of AP39, a Mitochondria-Targeted H2S Donor, on Mouse Mesenteric Artery Rings In Vitro

This is the final version. Available from MDPI via the DOI in this record. The data presented in this study are available on request from the corresponding author.Mitochondria-targeted hydrogen sulfide (H2S) donor compounds, such as compound AP39, supply H2S into the mitochondrial environment and have shown several beneficial in vitro and in vivo effects in cardiovascular conditions such as diabetes and hypertension. However, the study of their direct vascular effects has not been addressed to date. Thus, the objective of the present study was to analyze the effects and describe the mechanisms of action of AP39 on the in vitro vascular reactivity of mouse mesenteric artery. Protein and gene expressions of the H2S-producing enzymes (CBS, CSE, and 3MPST) were respectively analyzed by Western blot and qualitative RT-PCR, as well the in vitro production of H2S by mesenteric artery homogenates. Gene expression of CSE and 3MPST in the vessels has been evidenced by RT-PCR experiments, whereas the protein expression of all the three enzymes was demonstrated by Western blotting experiments. Nonselective inhibition of H2S-producing enzymes by AOAA abolished H2S production, whereas it was partially inhibited by PAG (a CSE selective inhibitor). Vasorelaxation promoted by AP39 and its H2S-releasing moiety (ADT-OH) were significantly reduced after endothelium removal, specifically dependent on NO-cGMP signaling and SKCa channel opening. Endogenous H2S seems to participate in the mechanism of action of AP39, and glibenclamide-induced KATP blockade did not affect the vasorelaxant response. Considering the results of the present study and the previously demonstrated antioxidant and bioenergetic effects of AP39, we conclude that mitochondria-targeted H2S donors may offer a new promising perspective in cardiovascular disease therapeutics.The Royal SocietySao Paulo Research Foundation (FAPESP)Sao Paulo Research Foundation (FAPESP)Brazilian National Council for Scientific and Technological Development (CNPq)Brazilian National Council for Scientific and Technological Development (CNPq)Coordination for the Improvement of Higher Education Personnel (CAPES

The experience of educational research at doctoral level in the region of Cuyo, Argentina

[EN] In this paper are reported the results of an exploratory-analytical research of a qualitative nature, whose intention is to approach the comprehension of the experiences, their peculiarities and problems, of a sample of students and graduates from the three doctorates in Education existing in the region of Cuyo, Argentina, which –though they reach a certain maturity– also show in these years some specific difficulties, among which the most relevant is the low rate of completion (close to 20%). The administered questionnaire, elaborated ad hoc, by means of open-ended questions, inquires on three dimensions that can explain the experience of the PhD student: 1) educational research methodology training, 2) practice in scientific research and 3) doctoral research process. The results show that curricular paths of doctorate’s research methodology, in dependence of their approach, play an important role in the process of theses, in synergy with other factors: integration into a research team, a combination of intrinsic and extrinsic motives in the choice of the topic, a more elaborated conceptualization of educational research, conceptual changes of greater importance. Among the peculiarities, one warns the primacy of the experience and/or teacher workplace in decisions concerning doctoral research; among the difficulties, stand out the lack of time and the major frequency of intrinsic difficulties to the thesis in delayed students.[ES] En este trabajo se informan los resultados de una investigación exploratorio-analítica de carácter cualitativo, cuyo propósito es acercarnos a la comprensión de las experiencias, sus particularidades y problemáticas, de una muestra de alumnos y egresados de los tres doctorados en Educación existentes en la región de Cuyo, Argentina, los que –si bien alcanzan una cierta madurez– también muestran en estos años algunas dificultades específicas, entre las cuales la más relevante es la baja tasa de finalización (cercana al 20%). El cuestionario que se administra, elaborado ad hoc, mediante preguntas abiertas, indaga sobre tres dimensiones que pueden explicar la experiencia del doctorando: 1) formación en metodología de la investigación educativa, 2) práctica en investigación científica y 3) proceso de investigación doctoral. Los resultados muestran que los trayectos curriculares de metodología de la investigación del doctorado, en dependencia de su enfoque, desempeñan un papel relevante en el proceso de tesis, en sinergia con otros factores: la inserción en un equipo de investigación, una combinación de motivos intrínsecos y extrínsecos en la elección del tema, una conceptualización más elaborada de investigación educativa, cambios conceptuales de mayor envergadura. Entre las peculiaridades, se advierte la primacía de la experiencia y/o desempeño docente en decisiones relativas a la investigación doctoral; entre las dificultades, destaca la falta de tiempo y la mayor frecuencia de dificultades intrínsecas a la tesis en los estudiantes demorados.Difabio De Anglat, H.; Portela De Nieto, A.; Gelonch Villarino, S.; Muscará, F.; Boarini De Dutto, MG. (2018). La experiencia de investigación educativa de nivel doctoral en la región de Cuyo, Argentina. 11-32. doi:10.4995/redu.2018.5690SWORD113

Daily cycling of nitric oxide synthase (NOS) in the hippocampus of pigeons (C. livia)

Background: Nitric oxide synthase (NOS) is essential for the synthesis of nitric oxide (NO), a non-conventional neurotransmitter with an important role in synaptic plasticity underlying processes of hippocampus-dependent memory and in the regulation of biological clocks and circadian rhythms. Many studies have shown that both the NOS cytosolic protein content and its enzymatic activity present a circadian variation in different regions of the rodent brain, including the hippocampus. The present study investigated the daily variation of NOS enzymatic activity and the cytosolic content of nNOS in the hippocampus of pigeons. Results: Adult pigeons kept under a skeleton photoperiod were assigned to six different groups. Homogenates of the hippocampus obtained at six different times-of-day were used for NOS analyses. Both iNOS activity and nNOS cytosolic protein concentrations were highest during the subjective light phase and lowest in the subjective dark phase of the circadian period. ANOVA showed significant time differences for iNOS enzymatic activity (p < 0.05) and for nNOS protein content (p < 0.05) in the hippocampus. A significant daily rhythm for both iNOS and nNOS was confirmed by analysis with the Cosinor method (p < 0.05). The present findings indicate that the enzymatic activity of iNOS and content of nNOS protein in the hippocampus of pigeons exhibit a daily rhythm, with acrophase values occurring during the behavioral activity phase. Conclusions: The data corroborate the reports on circadian variation of NOS in the mammalian hippocampus and can be considered indicative of a dynamic interaction between hippocampus-dependent processes and circadian clock mechanisms

Comparative Bioavailability Of Single Doses Of Tablet Formulations Of Cetirizine Dihydrochloride In Healthy Male Volunteers.

The bioavailability of two tablet formulations of cetirizine (Zetir from Abbott and Zyrtek from UCB) were compared in 14 healthy male volunteers who received a single dose of 10 mg of cetirizine dihydrochloride in an open randomized two-period crossover design with a 7-day washout period between doses. Plasma samples were obtained over a 24 h interval and cetirizine concentrations were determined by HPLC with ultraviolet detection. From the plasma cetirizine concentration vs. time curves, AUC(0-24) (area under the concentration vs. time curves from 0 to 24 h), Cmax (maximum achieved concentration), Tmax (time to achieve Cmax), Ke (terminal first order elimination constant), elimination half-life (t1/2) and AUC(0-infinity) (area under the concentration vs. time curves extrapolated to infinity) were obtained. The two cetirizine dihydrochloride tablet brands did not show statistically significant differences in bioavailability as assessed by analysis of AUC(0-24), AUC(0-infinity), Cmax, Tmax, Ke and t1/2 values. Based on these results and on the U.S. Food and Drug Administration requirements [1985, 1993], we conclude that both formulations are bioequivalent.3327-3