Person: Leite Fernandes, Vitor Samuel
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First Name
Vitor Samuel
Last Name
Leite Fernandes
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Fisiología
Area
Fisiología
Identifiers
6 results
Search Results
Now showing 1 - 6 of 6
Item The bitter taste receptor (TAS2R) agonist denatonium promotes a strong relaxation of rat corpus cavernosum(Biochemical Pharmacology, 2023) Navarro Dorado, Jorge; Climent Flórez, Belén; López-Oliva Muñoz, María Elvira; Martínez Sainz, María Del Pilar; Hernández Martín, Marina; Agis Torres, Ángel; Recio Visedo, María Paz; Barahona Gomáriz, María Victoria; Benedito Castellote, Sara; Leite Fernandes, Vitor Samuel; Hernández Rodríguez, Medardo VicenteBitter taste receptors (TAS2R) are found in numerous extra-oral tissues, including smooth muscle (SM) cells in both vascular and visceral tissues. Upon activation, TAS2R stimulate the relaxation of the SM. Nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling pathway is involved in penile erection, and type 5 phosphodiesterase (PDE5) inhibitors, a cGMP-specific hydrolase are used as first-line treatments for erectile dysfunction (ED). Nevertheless, PDE5 inhibitors are ineffective in a considerable number of patients, prompting research into alternative pharmacological targets for ED. Since TAS2R agonists regulate SM contractility, this study investigates the role of TAS2Rs in rat corpus cavernosum (CC). We performed immunohistochemistry to detect TAS2R10, isometric force recordings for TAS2R agonists denatonium and chloroquine, the slow-release H2S donor GYY 4137, the NO donor SNAP, the β-adrenoceptor agonist isoproterenol and electrical field stimulation (EFS), as well as measurement of endogenous hydrogen sulfide (H2S) production. The immunofluorescence staining indicated that TAS2R10 was broadly expressed in the CC SM and to some extent in the nerve fibers. Denatonium, chloroquine, SNAP, and isoproterenol cause potent dose-dependent SM relaxations. H2S production was decreased by NO and H2S synthase inhibitors, while it was enhanced by denatonium. In addition, denatonium increased the relaxations induced by GYY 4137 and SNAP but failed to modify EFS- and isoproterenol-induced responses. These results suggest neuronal and SM TAS2R10 expression in the rat CC, where denatonium induces a strong SM relaxation per se and promotes the H2S- and NO-mediated inhibitory gaseous neurotransmission. Thus, TAS2R10 might represent a valuable therapeutic target in ED.Item Endogenous Hydrogen Sulfide has a Powerful Role in Inhibitory Neurotransmission to the Pig Bladder Neck(Journal of Urology, 2013) Leite Fernandes, Vitor Samuel; Ribeiro, Ana S.F.; Martínez, María Pilar; Orensanz, Luis M.; Barahona Gomáriz, María Victoria; Martínez-Sáenz, Ana; Recio Visedo, María Paz; Benedito Castellote, Sara; Bustamante, Salvador; Carballido, Joaquín; García Sacristán, Albino; Prieto Ocejo, Dolores; Hernández Rodríguez, Medardo VicentePurpose: We investigated the possible involvement of H2S in nitric oxide independent inhibitory neurotransmission to the pig bladder neck. Materials and methods: We used immunohistochemistry to determine the expression of the H2S synthesis enzymes cystathionine γ-lyase and cystathionine β-synthase. We also used electrical field stimulation and myographs for isometric force recordings to study relaxation in response to endogenously released or exogenously applied H2S in urothelium denuded, phenylephrine precontracted bladder neck strips under noradrenergic, noncholinergic, nonnitrergic conditions. Results: Cystathionine γ-lyase and cystathionine β-synthase expression was observed in nerve fibers in the smooth muscle layer. Cystathionine γ-lyase and cystathionine β-synthase immunoreactive fibers were also identified around the small arteries supplying the bladder neck. Electrical field stimulation (2 to 16 Hz) evoked frequency dependent relaxation, which was decreased by DL-propargylglycine and abolished by tetrodotoxin (blockers of cystathionine γ-lyase and neuronal voltage gated Na(+) channels, respectively). The cystathionine β-synthase inhibitor O-(carboxymethyl)hydroxylamine did not change nerve mediated responses. The H2S donor GYY4137 (0.1 nM to 10 μM) induced potent, concentration dependent relaxation, which was not modified by neuronal voltage gated Na(+) channels, or cystathionine γ-lyase or cystathionine β-synthase blockade. Conclusions: Results suggest that endogenous H2S synthesized by cystathionine γ-lyase and released from intramural nerves acts as a powerful signaling molecule in nitric oxide independent inhibitory transmission to the pig bladder neck.Item In vitro inhibition of phosphodiesterase type 4 enhances rat corpus cavernosum nerve-mediated relaxation induced by gasotransmitters(Life Sciences, 2022) Leite Fernandes, Vitor Samuel; López-Oliva Muñoz, María Elvira; Martínez Sainz, María Del Pilar; Agis Torres, Ángel; Recio Visedo, María Paz; Navarro Dorado, Jorge; Barahona Gomáriz, María Victoria; Benedito Castellote, Sara; Prieto Ocejo, Dolores; Climent Flórez, Belén; Hernández Rodríguez, Medardo VicenteAims: Nitric oxide (NO) and hydrogen sulfide (H2S) are involved in nerve-mediated corpus cavernosum (CC) relaxation. Expression of phosphodiesterase type 5 (PDE5) and type 4 (PDE4), cyclic guanosine monophosphate (cGMP)- and cyclic adenosine monophosphate (cAMP)-specific, respectively, has been described and PDE5- and PDE4-inhibitors induce cavernous smooth muscle relaxation. Whereas the NO/cGMP signaling pathway is well established in penile erection, the cAMP-mediated mechanism is not fully elucidated. The aim of this study is to investigate the localization and the functional significance of PDE4 in rat CC tone regulation. Main methods: We performed immunohistochemistry for the detection of the PDE4A isoenzyme. Isometric tension recordings for roflumilast and tadalafil, PDE4 and PDE5 inhibitors, respectively, electrical field stimulation (EFS) and β-adrenoceptor agonist isoproterenol and endogenous H2S production measurement. Key findings: A marked PDE4A expression was detected mainly localized in the nerve cells of the cavernous smooth muscle. Furthermore, roflumilast and tadalafil exhibited strong corpus cavernous relaxations. Endoge-nous H2S production was decreased by NO and H2S synthase inhibitors and increased by roflumilast. Isopro-terenol- and EFS-induced relaxations were increased by roflumilast. Significance: These results indicate that PDE4A is mainly expressed within the nerves cells of the rat CC, where roflumilast induces a potent corpus cavernous relaxation per se and potentiates the response induced by β-adrenoceptor activation. The fact that roflumilast enhances H2S production, as well as EFS-elicited responses suggests that PDE4 inhibitors modulate, in a positive feedback fashion, nerve-mediated relaxation induced by gasotransmitters, thus indicating a key role for neuronal PDE4 in penile erection.Item Hydrogen sulfide mediated inhibitory neurotransmission to the pig bladder neck: role of KATP channels, sensory nerves and calcium signaling.(Journal of Urology, 2013) Leite Fernandes, Vitor Samuel; Fernandes Ribeiro, Ana Sofía; Barahona Gomáriz, María Victoria; Orensanz Muñoz, Luis Miguel; Martínez Sáenz, Ana; Recio Visedo, María Paz; Martínez Gómez, Ana Cristina; Bustamante, Salvador; Carballido, Joaquín; García Sacristán, Albino; Prieto Ocejo, Dolores; Hernández Rodríguez, Medardo VicentePurpose: Because neuronal released endogenous H2S has a key role in relaxation of the bladder outflow region, we investigated the mechanisms involved in H2S dependent inhibitory neurotransmission to the pig bladder neck. Materials and methods: Bladder neck strips were mounted in myographs for isometric force recording and simultaneous measurement of intracellular Ca(2+) and tension. Results: On phenylephrine contracted preparations electrical field stimulation and the H2S donor GYY4137 evoked frequency and concentration dependent relaxation, which was reduced by desensitizing capsaicin sensitive primary afferents with capsaicin, and the blockade of adenosine 5'-triphosphate dependent K(+) channels, cyclooxygenase and cyclooxygenase-1 with glibenclamide, indomethacin and SC560, respectively. Inhibition of vanilloid, transient receptor potential A1, transient receptor potential vanilloid 1, vasoactive intestinal peptide/pituitary adenylyl cyclase-activating polypeptide and calcitonin gene-related peptide receptors with capsazepine, HC030031, AMG9810, PACAP6-38 and CGRP8-37, respectively, also decreased electrical field stimulation and GYY4137 responses. H2S relaxation was not changed by guanylyl cyclase, protein kinase A, or Ca(2+) activated or voltage gated K(+) channel inhibitors. GYY4137 inhibited the contractions induced by phenylephrine and by K(+) enriched (80 mM) physiological saline solution. To a lesser extent it decreased the phenylephrine and K(+) induced increases in intracellular Ca(2+). Conclusions: H2S produces pig bladder neck relaxation via activation of adenosine 5'-triphosphate dependent K(+) channel and by smooth muscle intracellular Ca(2+) desensitization dependent mechanisms. H2S also promotes the release of sensory neuropeptides and cyclooxygenase-1 pathway derived prostanoids from capsaicin sensitive primary afferents via transient receptor potential A1, transient receptor potential vanilloid 1 and/or related ion channel activation. Keywords: 4-AP; 4-aminopyridine; AM; ATP; ATP dependent K(+); CGRP; COX; CSE; CSPA; Ca(2+) activated K(+); Emax; K(ATP); K(Ca); K(V); KPSS; L-NOARG; MLCP; N(G)-nitro-L-arginine; NO; PACAP; PKA; PSS; TRPA(1); TRPV(1); VOC; VPAC; [Ca(2+)](i); acetoxymethyl ester; adenosine 5′-triphosphate; calcitonin gene-related peptide; capsaicin sensitive primary afferent; cyclooxygenase; cystathionine γ-lyase; hydrogen sulfide; intracellular Ca(2+); maximum response; muscle, smooth; myosin light chain phosphatase; nitric oxide; physiological saline solution; pituitary adenylyl cyclase activating polypeptide; potassium channels; potassium rich PSS; protein kinase A; synaptic transmission; transient receptor potential A1; transient receptor potential vanilloid 1; urinary bladder; vasoactive intestinal peptide receptor; voltage gated Ca(2+); voltage gated K(+).Item Phosphodiesterase type 4 inhibition enhances nitric oxide- and hydrogen sulfide-mediated bladder neck inhibitory neurotransmission(Scientific Reports, 2018) Agis Torres, Ángel; Recio Visedo, María Paz; López-Oliva Muñoz, María Elvira; Martínez Sainz, María Del Pilar; Barahona Gomáriz, María Victoria; Benedito Castellote, Sara; Bustamante, Salvador; Jiménez-Cidre; Miguel Ángel; García Sacristán, Albino; Prieto Ocejo, Dolores; Leite Fernandes, Vitor Samuel; Hernández Rodríguez, Medardo VicenteNitric oxide (NO) and hydrogen sulfide (H2S) play a pivotal role in nerve-mediated relaxation of the bladder outflow region. In the bladder neck, a marked phosphodiesterase type 4 (PDE4) expression has also been described and PDE4 inhibitors, as rolipram, produce smooth muscle relaxation. This study investigates the role of PDE4 isoenzyme in bladder neck gaseous inhibitory neurotransmission. We used Western blot and double immunohistochemical staining for the detection of NPP4 (PDE4) and PDE4A and organ baths for isometric force recording to roflumilast and tadalafil, PDE4 and PDE5, respectively, inhibitors in pig and human samples. Endogenous H2S production measurement and electrical field stimulation (EFS) were also performed. A rich PDE4 and PDE4A expression was observed mainly limited to nerve fibers of the smooth muscle layer of both species. Moreover, roflumilast produced a much more potent smooth muscle relaxation than that induced by tadalafil. In porcine samples, H2S generation was diminished by H2S and NO synthase inhibition and augmented by roflumilast. Relaxations elicited by EFS were potentiated by roflumilast. These results suggest that PDE4, mainly PDE4A, is mostly located within nerve fibers of the pig and human bladder neck, where roflumilast produces a powerful smooth muscle relaxation. In pig, the fact that roflumilast increases endogenous H2S production and EFS-induced relaxations suggests a modulation of PDE4 on NO- and H2S-mediated inhibitory neurotransmission.Item Mechanisms involved in endothelin‐1‐induced contraction of the pig urinary bladder neck(Neurourology and urodynamics, 2011) Arteaga, José Luis; Orensanz Muñoz, Luis Miguel; Martínez, María Pilar; Barahona Gomáriz, María Victoria; Recio Visedo, María Paz; Martínez Sáenz, Ana; Leite Fernandes, Vitor Samuel; Fernandes Ribeiro, Ana Sofía; García Sacristán, Albino; Prieto Ocejo, Dolores; Hernández Rodríguez, Medardo VicenteAims: There is no information about the signaling pathways involved in the endothelin-1 (ET-1)-induced contraction of bladder neck. The current study investigates the mechanisms involved in the ET-1-elicited contraction in the pig bladder neck. Methods: Bladder neck strips were mounted in organ baths containing physiological saline solution at 378C and gassed with 95% O2 and 5% CO2, for isometric force recording to endothelin receptor agonists, noradrenaline (NA), and electrical field stimulation. Endothelin ETA receptor expression was also determined, by both immunohistochemistry and Western blot. Results: ETA receptor expression (Western blot) was observed in the muscular layer and urothelium. A strong ETA-immunoreactivity (ETA-IR) was identified within nerve fibers among smooth muscle bundles. ET-1 and ET-2 evoked similar concentration-dependent contractions of urothelium-denuded preparations. ET-3 produced a slight response, whereas the ETB receptor agonist BQ3020 failed to promote contraction. BMS182874, an ETA receptor antagonist, reduced ET-1-induced contraction whereas BQ788, an ETB antagonist, did not change such responses. ET-1 contractions were reduced by extracellular Ca2þ removal and by inhibition of voltage-gated Ca2þ (VOC) (L-type) and non-VOC channels, Rho/Rho-kinase pathway, and neuronal VOC channels. NA produced contractions which were enhanced by ET-1 threshold concentrations. ETA receptor blockade enhanced nitric oxide-dependent nerve-mediated relaxations. Conclusions: These results suggest that ET-1 produces contraction via muscular ETA receptors coupled to extracellular Ca2þ entry via VOC (L-type) and non-VOC channels. Intracellular Ca2þ mobilization and a Rho/Rho-kinase pathway could also be involved in these responses. ET-1-evoked potentiation on noradrenergic contraction, and neuronal ETA receptors modulating nitrergic inhibitory neurotransmission, are also demonstrated. Neurourol. Urodynam. 31:156–161, 2012. 2011 Wiley Periodicals, Inc.