RESUMEN
Bitter 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 ß-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.
Asunto(s)
Cloroquina , Gusto , Masculino , Animales , Ratas , Isoproterenol , GMP CíclicoRESUMEN
AIMS: 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 ß-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. Endogenous H2S production was decreased by NO and H2S synthase inhibitors and increased by roflumilast. Isoproterenol- 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 ß-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.
Asunto(s)
Aminopiridinas/farmacología , Benzamidas/farmacología , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/metabolismo , Gasotransmisores/metabolismo , Pene/fisiología , 3',5'-AMP Cíclico Fosfodiesterasas/metabolismo , Aminopiridinas/administración & dosificación , Animales , Benzamidas/administración & dosificación , Ciclopropanos/administración & dosificación , Ciclopropanos/farmacología , Relación Dosis-Respuesta a Droga , Sulfuro de Hidrógeno/metabolismo , Masculino , Relajación Muscular/efectos de los fármacos , Nitroarginina/farmacología , Pene/efectos de los fármacos , Nervios Periféricos/efectos de los fármacos , Nervios Periféricos/fisiología , Ratas Wistar , Tadalafilo/farmacologíaRESUMEN
BACKGROUND AND PURPOSE: Obesity is a risk factor for the development of chronic kidney disease independent of diabetes, hypertension and other co-morbidities. Obesity-associated nephropathy is linked to dysregulation of the cell energy sensor AMP-activated protein kinase (AMPK). We aimed here to assess whether impairment of AMPK activity may cause renal arterial dysfunction in obesity and to evaluate the therapeutic potential of activating renal AMPK. EXPERIMENTAL APPROACH: Effects of the AMPK activator A769662 were assessed on intrarenal arteries isolated from ob/ob mice and obese Zucker rats and then mounted in microvascular myographs. Superoxide and hydrogen peroxide production were measured by chemiluminescence and fluorescence, respectively, and protein expression was analysed by western blotting. KEY RESULTS: Endothelium-dependent vasodilation and PI3K/Akt/eNOS pathway were impaired in preglomerular arteries from genetically obese rats and mice, along with impaired arterial AMPK activity and blunted relaxations induced by the AMPK activator A769662. Acute ex vivo exposure to A769662 restored endothelial function and enhanced activity of PI3K/Akt/eNOS pathway in obese rats, whereas in vivo treatment with A769662 improved metabolic state and ameliorated endothelial dysfunction, reduced inflammatory markers and vascular oxidative stress in renal arteries and restored redox balance in renal cortex of obese mice. CONCLUSION AND IMPLICATIONS: These results demonstrate that AMPK dysregulation underlies obesity-associated kidney vascular dysfunction and activation of AMPK improves metabolic state, protects renal endothelial function and exerts potent vascular antioxidant and anti-inflammatory effects. The beneficial effects of vascular AMPK activation might represent a promising therapeutic approach to the treatment of obesity-related kidney injury.
Asunto(s)
Adenilato Quinasa , Endotelio Vascular , Proteínas Quinasas Activadas por AMP/metabolismo , Adenilato Quinasa/metabolismo , Animales , Endotelio Vascular/metabolismo , Inflamación/metabolismo , Riñón/metabolismo , Ratones , Obesidad/metabolismo , Estrés Oxidativo , Fosfatidilinositol 3-Quinasas/metabolismo , Ratas , Ratas Zucker , Arteria Renal , Roedores/metabolismo , VasodilataciónRESUMEN
AMP-activated protein kinase (AMPK) is a cellular energy sensor activated during energy stress to stimulate ATP production pathways and restore homeostasis. AMPK is widely expressed in the kidney and involved in mitochondrial protection and biogenesis upon acute renal ischemia, AMPK activity being blunted in metabolic disease-associated kidney disease. Since little is known about AMPK in the regulation of renal blood flow, the present study aimed to assess the role of AMPK in renal vascular function. Functional responses to the selective AMPK activator A769662 were assessed in intrarenal small arteries isolated from the kidney of renal tumour patients and Wistar rats and mounted in microvascular myographs to perform simultaneous measurements of intracellular calcium [Ca2+]i and tension. Superoxide (O2.-) and hydrogen peroxide (H2O2) production were measured by chemiluminescence and fluorescence and protein expression by Western blot. Activation of AMPK with A769662 increased AMPKα phosphorylation at Thr-172 and induced potent relaxations compared to AICAR in isolated human and rat intrarenal arteries, through both endothelium-dependent mechanisms involving nitric oxide (NO) and intermediate-conductance calcium-activated potassium (IKCa) channels, as well as activation of ATP-sensitive (KATP) channels and sarcoplasmic reticulum Ca2+-ATPase (SERCA) in vascular smooth muscle (VSM). Furthermore, AMPK activator reduced NADPH oxidase 4 (Nox4) and Nox2-derived reactive oxygen species (ROS) production. These results demonstrate that A769662 has potent vasodilator and antioxidant effects in intrarenal arteries. The benefits of AMPK activation in rat kidney are reproduced in human arteries and therefore vascular AMPK activation might be a therapeutic target in the treatment of metabolic disease-associated kidney injury.
Asunto(s)
Proteínas Quinasas Activadas por AMP , Vasodilatación , Proteínas Quinasas Activadas por AMP/genética , Adenosina Monofosfato , Adenilato Quinasa , Animales , Humanos , Peróxido de Hidrógeno , Riñón , Ratas , Ratas Wistar , Especies Reactivas de OxígenoRESUMEN
Oxidative stress-associated endothelial dysfunction is a key pathogenic factor underlying the microvascular complications of metabolic disease. NADPH oxidase (Nox) is a major source of oxidative stress in diabetic nephropathy and chronic kidney disease, despite Nox4 and Nox2 have been identified as relevant sources of vasodilator endothelial H2O2.The present study was sought to investigate the role of Nox enzymes in renal vascular oxidative stress and endothelial dysfunction in a rat model of genetic obesity. Endothelial function was assessed in intrarenal arteries of obese Zucker rats (OZR) and their counterparts lean Zucker rats (LZR) mounted in microvascular myographs, and superoxide (O2.-) and H2O2 production were measured. Impaired endothelium-dependent relaxations to acetylcholine (ACh) were associated to augmented O2.- generation, but neither ROS scavengers nor the Nox inhibitor apocynin significantly improved these relaxant responses in renal arteries of OZR. Whereas NO contribution to endothelial relaxations was blunted, catalase-sensitive non-NO non-prostanoid relaxations were enhanced in obese rats. Interestingly, NADPH-dependent O2.- production was augmented while NADPH-dependent H2O2 generation was reduced, and cytosolic and mitochondrial SOD were up-regulated in kidney of obese rats. Nox4 was down-regulated in renal arteries and Nox4-dependent H2O2 generation and endothelial relaxation were reduced in OZR. Up-regulation of both Nox2 and Nox1 was associated with augmented O2.- production but reduced H2O2 generation and blunted endothelial Nox2-derived H2O2-mediated in obese rats. Moreover, increased Nox1-derived O2.- contributed to renal endothelial dysfunction in OZR. In summary, the current data support a main role for Nox1-derived O2.- in kidney vascular oxidative stress and renal endothelial dysfunction in obesity, while reduced endothelial Nox4 expression associated to decreased H2O2 generation and H2O2-mediated vasodilatation might hinder Nox4 protective renal effects thus contributing to kidney injury. This suggests that effective therapies to counteract oxidative stress and prevent microvascular complications must identify the specific Nox subunits involved in metabolic disease.
Asunto(s)
Endotelio Vascular/metabolismo , NADPH Oxidasa 1/genética , NADPH Oxidasa 2/genética , NADPH Oxidasa 4/genética , Obesidad/etiología , Obesidad/metabolismo , Estrés Oxidativo , Animales , Antioxidantes/metabolismo , Susceptibilidad a Enfermedades , Peróxido de Hidrógeno/metabolismo , Inmunohistoquímica , Riñón/metabolismo , Riñón/patología , Masculino , Metabolómica , Modelos Biológicos , NADPH Oxidasa 1/metabolismo , NADPH Oxidasa 2/metabolismo , NADPH Oxidasa 4/metabolismo , Obesidad/patología , Ratas , Especies Reactivas de Oxígeno/metabolismo , Arteria Renal/metabolismo , Arteria Renal/fisiopatología , Superóxidos/metabolismoRESUMEN
PURPOSE: This study investigates whether functionality and/or expression changes of transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1) channels, oxidative stress, and hydrogen sulfide (H2S) are involved in the bladder dysfunction from an insulin-resistant obese Zucker rat (OZR). MATERIALS AND METHODS: Detrusor smooth muscle (DSM) samples from the OZR and their respective controls, a lean Zucker rat (LZR), were processed for immunohistochemistry for studying the expression of TRPA1 and TRPV1 and the H2S synthase cystathionine beta-synthase (CBS) and cysthathionine-γ-lyase (CSE). Isometric force recordings to assess the effects of TRPA1 agonists and antagonists on DSM contractility and measurement of oxidative stress and H2S production were also performed. RESULTS: Neuronal TRPA1 expression was increased in the OZR bladder. Electrical field stimulation- (EFS-) elicited contraction was reduced in the OZR bladder. In both LZR and OZR, TRPA1 activation failed to modify DSM basal tension but enhanced EFS contraction; this response is inhibited by the TRPA1 blockade. In the OZR bladder, reactive oxygen species, malondialdehyde, and protein carbonyl contents were increased and antioxidant enzyme activities (superoxide dismutase, catalase, GR, and GPx) were diminished. CSE expression and CSE-generated H2S production were also reduced in the OZR. Both TRPV1 and CBS expressions were not changed in the OZR. CONCLUSIONS: These results suggest that an increased expression and functionality of TRPA1, an augmented oxidative stress, and a downregulation of the CSE/H2S pathway are involved in the impairment of nerve-evoked DSM contraction from the OZR.
Asunto(s)
Sulfuro de Hidrógeno/metabolismo , Resistencia a la Insulina , Obesidad , Estrés Oxidativo , Canal Catiónico TRPA1/metabolismo , Enfermedades de la Vejiga Urinaria , Vejiga Urinaria , Animales , Cistationina betasintasa , Cistationina gamma-Liasa , Masculino , Contracción Muscular , Músculo Liso , Obesidad/metabolismo , Obesidad/patología , Obesidad/fisiopatología , Ratas , Ratas Zucker , Vejiga Urinaria/metabolismo , Vejiga Urinaria/patología , Vejiga Urinaria/fisiopatología , Enfermedades de la Vejiga Urinaria/metabolismo , Enfermedades de la Vejiga Urinaria/patología , Enfermedades de la Vejiga Urinaria/fisiopatologíaRESUMEN
The role of NADPH oxidase (Nox)-derived reactive oxygen species in kidney vascular function has extensively been investigated in the harmful context of oxidative stress in diabetes and obesity-associated kidney disease. Since hydrogen peroxide (H2O2) has recently been involved in the non-nitric oxide (NO) non-prostanoid relaxations of intrarenal arteries, the present study was sought to investigate whether NADPH oxidases may be functional sources of vasodilator H2O2 in the kidney and to assess their role in the endothelium-dependent relaxations of human and rat intrarenal arteries. Renal interlobar arteries isolated from the kidney of renal tumor patients who underwent nephrectomy, and from the kidney of Wistar rats, were mounted in microvascular myographs to assess function. Superoxide (O2.-) and H2O2 production was measured by chemiluminescence and Amplex Red fluorescence, and Nox2 and Nox4 enzymes were detected by Western blotting and by double inmunolabeling along with eNOS. Nox2 and Nox4 proteins were expressed in the endothelium of renal arterioles and glomeruli co-localized with eNOS, levels of expression of both enzymes being higher in the cortex than in isolated arteries. Pharmacological inhibition of Nox with apocynin and of CYP 2C epoxygenases with sulfaphenazol, but not of the NO synthase (NOS), reduced renal NADPH-stimulated O2.- and H2O2 production. Under conditions of cyclooxygenase and NOS blockade, acetylcholine induced endothelium-dependent relaxations that were blunted by the non-selective Nox inhibitor apocynin and by the Nox2 or the Nox1/4 inhibitors gp91ds-tat and GKT136901, respectively. Acetylcholine stimulated H2O2 production that was reduced by gp91ds-tat and by GKT136901. These results suggest the specific involvement of Nox4 and Nox2 subunits as physiologically relevant endothelial sources of H2O2 generation that contribute to the endothelium-dependent vasodilatation of renal arteries and therefore have a protective role in kidney vasculature.
Asunto(s)
Arterias/fisiología , Endotelio Vascular/fisiología , Peróxido de Hidrógeno/metabolismo , Riñón/irrigación sanguínea , NADPH Oxidasa 2/metabolismo , NADPH Oxidasa 4/metabolismo , Vasodilatación , Anciano , Animales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ratas WistarRESUMEN
Nitric 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.
Asunto(s)
Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/química , Sulfuro de Hidrógeno/metabolismo , Óxido Nítrico/metabolismo , Inhibidores de Fosfodiesterasa 4/farmacología , Transmisión Sináptica/efectos de los fármacos , Vejiga Urinaria/metabolismo , Adulto , Anciano , Animales , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Rolipram/farmacología , Porcinos , Vejiga Urinaria/efectos de los fármacos , Vejiga Urinaria/patologíaRESUMEN
Reactive oxygen species (ROS) like hydrogen peroxide (H2O2) are involved in the in endothelium-derived hyperpolarization (EDH)-type relaxant responses of coronary and mesenteric arterioles. The role of ROS in kidney vascular function has mainly been investigated in the context of harmful ROS generation associated to kidney disease. The present study was sought to investigate whether H2O2 is involved in the endothelium-dependent relaxations of intrarenal arteries as well the possible endothelial sources of ROS generation involved in these responses. Under conditions of cyclooxygenase (COX) and nitric oxide (NO) synthase inhibition, acetylcholine (ACh) induced relaxations and stimulated H2O2 release that were reduced by catalase and by the glutathione peroxidase (GPx) mimetic ebselen in rat renal interlobar arteries, suggesting the involvement of H2O2 in the endothelium-dependent responses. ACh relaxations were also blunted by the CYP2C inhibitor sulfaphenazole and by the NADPH oxidase inhibitor apocynin. Acetylcholine stimulated both superoxide (O2â¢-) and H2O2 production that were reduced by sulfaphenazole and apocynin. Expression of the antioxidant enzyme CuZnSOD and of the H2O2 reducing enzymes catalase and GPx-1 was found in both intrarenal arteries and renal cortex. On the other hand, exogenous H2O2 relaxed renal arteries by decreasing vascular smooth muscle (VSM) intracellular calcium concentration [Ca2+]i and markedly enhanced endothelial KCa currents in freshly isolated renal endothelial cells. CYP2C11 and CYP2C23 epoxygenases were highly expressed in interlobar renal arteries and renal cortex, respectively, and were co-localized with eNOS in renal endothelial cells. These results demonstrate that H2O2 is involved in the EDH-type relaxant responses of renal arteries and that CYP 2C epoxygenases are physiologically relevant endothelial sources of vasodilator H2O2 in the kidney.
Asunto(s)
Hidrocarburo de Aril Hidroxilasas/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Familia 2 del Citocromo P450/metabolismo , Peróxido de Hidrógeno/metabolismo , Riñón/metabolismo , Músculo Liso Vascular/metabolismo , Esteroide 16-alfa-Hidroxilasa/metabolismo , Acetofenonas/administración & dosificación , Acetilcolina/metabolismo , Animales , Arterias/efectos de los fármacos , Arterias/metabolismo , Factores Biológicos/metabolismo , Calcio/metabolismo , Citocromo P-450 CYP2J2 , Endotelio/efectos de los fármacos , Endotelio/metabolismo , Humanos , Riñón/patología , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/patología , NADPH Oxidasas/metabolismo , Óxido Nítrico Sintasa/genética , Óxido Nítrico Sintasa de Tipo III , Prostaglandina-Endoperóxido Sintasas/genética , Prostaglandina-Endoperóxido Sintasas/metabolismo , Ratas , Especies Reactivas de Oxígeno/metabolismo , Relajación , Sulfafenazol/administración & dosificación , Superóxidos/metabolismoRESUMEN
Hydrogen sulfide (H2S) is a gasotransmitter employed for intra- and inter-cellular communication in almost all organ systems. This study investigates the role of endogenous H2S in nerve-evoked relaxation of pig terminal bronchioles with 260 µm medium internal lumen diameter. High expression of the H2S synthesis enzyme cystathionine γ-lyase (CSE) in the bronchiolar muscle layer and strong CSE-immunoreactivity within nerve fibers distributed along smooth muscle bundles were observed. Further, endogenous H2S generated in bronchiolar membranes was reduced by CSE inhibition. In contrast, cystathionine ß-synthase expression, another H2S synthesis enzyme, however was not consistently detected in the bronchiolar smooth muscle layer. Electrical field stimulation (EFS) and the H2S donor P-(4-methoxyphenyl)-P-4-morpholinylphosphinodithioic acid (GYY4137) evoked smooth muscle relaxation. Inhibition of CSE, nitric oxide (NO) synthase, soluble guanylyl cyclase (sGC) and of ATP-dependent K+, transient receptor potential A1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) channels reduced the EFS relaxation but failed to modify the GYY4137 response. Raising extracellular K+ concentration inhibited the GYY4137 relaxation. Large conductance Ca2+-activated K+ channel blockade reduced both EFS and GYY4137 responses. GYY4137 inhibited the contractions induced by histamine and reduced to a lesser extent the histamine-induced increases in intracellular [Ca2+]. These results suggest that relaxation induced by EFS in the pig terminal bronchioles partly involves the H2S/CSE pathway. H2S response is produced via NO/sGC-independent mechanisms involving K+ channels and intracellular Ca2+ desensitization-dependent pathways. Thus, based on our current results H2S donors might be useful as bronchodilator agents for the treatment of lung diseases with persistent airflow limitation, such as asthma and chronic obstructive lung disease.
Asunto(s)
Bronquiolos/metabolismo , Cistationina gamma-Liasa/metabolismo , Sulfuro de Hidrógeno/metabolismo , Guanilil Ciclasa Soluble/metabolismo , Animales , Proteínas de Unión al Calcio/metabolismo , Femenino , Histamina/metabolismo , Masculino , Morfolinas/farmacología , Relajación Muscular/fisiología , Músculo Liso/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/metabolismo , Compuestos Organotiofosforados/farmacología , Canales de Potasio/metabolismo , PorcinosRESUMEN
Metabolic syndrome (MS) is a known risk factor for lower urinary tract symptoms. This study investigates whether functional and expression changes of cannabinoid CB1 and CB2 receptors are involved in the bladder dysfunction in an obese rat model with insulin resistance. Bladder samples from obese Zucker rat (OZR) and their respective controls lean Zucker rat (LZR) were processed for immunohistochemistry and western blot for studying the cannabinoid receptors expression. Detrusor smooth muscle (DSM) strips from LZR and OZR were also mounted in myographs for isometric force recordings. Neuronal and smooth muscle CB1 and CB2 receptor expression and the nerve fiber density was diminished in the OZR bladder. Electrical field stimulation (EFS) and acetylcholine (ACh) induced frequency- and concentration-dependent contractions of LZR and OZR DSM. ACh contractile responses were similar in LZR and OZR. EFS-elicited contractions, however, were reduced in OZR bladder. Cannabinoid receptor agonists and antagonists failed to modify the DSM basal tension in LZR and OZR In LZR bladder, EFS responses were inhibited by ACEA and SER-601, CB1 and CB2 receptor agonists, respectively, these effects being reversed by ACEA plus the CB1 antagonist, AM-251 or SER-601 plus the CB2 antagonist, AM-630. In OZR bladder, the inhibitory action of ACEA on nerve-evoked contractions was diminished, whereas that SER-601 did not change EFS responses. These results suggest that a diminished function and expression of neuronal cannabinoid CB1 and CB2 receptors, as well as a lower nerve fiber density is involved in the impaired excitatory neurotransmission of the urinary bladder from the OZR.
Asunto(s)
Obesidad/fisiopatología , Receptor Cannabinoide CB1/análisis , Receptor Cannabinoide CB2/análisis , Transmisión Sináptica , Vejiga Urinaria/inervación , Vejiga Urinaria/fisiopatología , Animales , Masculino , Contracción Muscular , Músculo Liso/inervación , Músculo Liso/patología , Músculo Liso/fisiopatología , Fibras Nerviosas/patología , Obesidad/patología , Ratas , Ratas Zucker , Receptor Cannabinoide CB1/metabolismo , Receptor Cannabinoide CB2/metabolismo , Vejiga Urinaria/patologíaRESUMEN
This MiniReview focuses on the role played by nitric oxide (NO) and hydrogen sulfide (H2 S) in physiology of the upper and lower urinary tract. NO and H2 S, together with carbon monoxide, belong to the group of gaseous autocrine/paracrine messengers or gasotransmitters, which are employed for intra- and intercellular communication in almost all organ systems. Because they are lipid-soluble gases, gaseous transmitters are not constrained by cellular membranes, so that their storage in vesicles for later release is not possible. Gasotransmitter signals are terminated by falling concentrations upon reduction in production that are caused by reacting with cellular components (essentially reactive oxygen species and NO), binding to cellular components or diffusing away. NO and, more recently, H2 S have been identified as key mediators in neurotransmission of the urinary tract, involved in the regulation of ureteral smooth muscle activity and urinary flow ureteral resistance, as well as by playing a crucial role in the smooth muscle relaxation of bladder outlet region. Urinary bladder function is also dependent on integration of inhibitory mediators, such as NO, released from the urothelium. In the bladder base and distal ureter, the co-localization of neuronal NO synthase with substance P and calcitonin gene-related peptide in sensory nerves as well as the existence of a high nicotinamide adenine dinucleotide phosphate-diaphorase activity in dorsal root ganglion neurons also suggests the involvement of NO as a sensory neurotransmitter.
Asunto(s)
Sulfuro de Hidrógeno/metabolismo , Modelos Biológicos , Óxido Nítrico/metabolismo , Fenómenos Fisiológicos del Sistema Urinario , Sistema Urinario/metabolismo , Animales , Humanos , Neuronas Motoras/fisiología , Relajación Muscular , Músculo Liso/irrigación sanguínea , Músculo Liso/inervación , Músculo Liso/fisiología , Músculo Liso Vascular/inervación , Músculo Liso Vascular/fisiología , Terminaciones Nerviosas/fisiología , Neuronas Aferentes/fisiología , Sistema Urinario/irrigación sanguínea , Sistema Urinario/inervaciónRESUMEN
AIMS: Neuronal and non-neuronal bradykinin (BK) receptors regulate the contractility of the bladder urine outflow region. The current study investigates the role of BK receptors in the regulation of the smooth muscle contractility of the pig intravesical ureter. METHODS: Western blot and immunohistochemistry were used to show the expression of BK B1 and B2 receptors and myographs for isometric force recordings. RESULTS: B2 receptor expression was consistently detected in the intravesical ureter urothelium and smooth muscle layer, B1 expression was not detected where a strong B2 immunoreactivity was observed within nerve fibers among smooth muscle bundles. On ureteral strips basal tone, BK induced concentration-dependent contractions, were potently reduced by extracellular Ca(2+) removal and by B2 receptor and voltage-gated Ca(2+) (VOC) channel blockade. BK contraction did not change as a consequence of urothelium mechanical removal or cyclooxygenase and Rho-associated protein kinase inhibition. On 9,11-dideoxy-9a,11a-methanoepoxy prostaglandin F2α (U46619)-precontracted samples, under non-adrenergic non-cholinergic (NANC) and nitric oxide (NO)-independent NANC conditions, electrical field stimulation-elicited frequency-dependent relaxations which were reduced by B2 receptor blockade. Kallidin, a B1 receptor agonist, failed to increase preparation basal tension or to induce relaxation on U46619-induced tone. CONCLUSIONS: The present results suggest that BK produces contraction of pig intravesical ureter via smooth muscle B2 receptors coupled to extracellular Ca(2+) entry mainly via VOC (L-type) channels. Facilitatory neuronal B2 receptors modulating NO-dependent or independent NANC inhibitory neurotransmission are also demonstrated.
Asunto(s)
Contracción Muscular/fisiología , Músculo Liso/metabolismo , Receptor de Bradiquinina B2/metabolismo , Uréter/metabolismo , Animales , Bradiquinina/farmacología , Femenino , Calidina/farmacología , Masculino , Contracción Muscular/efectos de los fármacos , Relajación Muscular/efectos de los fármacos , Relajación Muscular/fisiología , Músculo Liso/efectos de los fármacos , Receptor de Bradiquinina B1/metabolismo , Porcinos , Uréter/efectos de los fármacos , Urotelio/efectos de los fármacos , Urotelio/metabolismo , Vasodilatadores/farmacologíaRESUMEN
Obesity is related to vascular dysfunction through inflammation and oxidative stress and it has been identified as a risk factor for chronic renal disease. In the present study, we assessed the specific relationships among reactive oxygen species (ROS), cyclooxygenase 2 (COX-2), and endothelial dysfunction in renal interlobar arteries from a genetic model of obesity/insulin resistance, the obese Zucker rats (OZR). Relaxations to acetylcholine (ACh) were significantly reduced in renal arteries from OZR compared to their counterpart, the lean Zucker rat (LZR), suggesting endothelial dysfunction. Blockade of COX with indomethacin and with the selective blocker of COX-2 restored the relaxations to ACh in obese rats. Selective blockade of the TXA2/PGH2 (TP) receptor enhanced ACh relaxations only in OZR, while inhibition of the prostacyclin (PGI2) receptor (IP) enhanced basal tone and inhibited ACh vasodilator responses only in LZR. Basal production of superoxide was increased in arteries of OZR and involved NADPH and xanthine oxidase activation and NOS uncoupling. Under conditions of NOS blockade, ACh induced vasoconstriction and increased ROS generation that were augmented in arteries from OZR and blunted by COX-2 inhibition and by the ROS scavenger tempol. Hydrogen peroxide (H2O2) evoked both endothelium- and vascular smooth muscle (VSM)-dependent contractions, as well as ROS generation that was reduced by COX-2 inhibition. In addition, COX-2 expression was enhanced in both VSM and endothelium of renal arteries from OZR. These results suggest that increased COX-2-dependent vasoconstriction contributes to renal endothelial dysfunction through enhanced (ROS) generation in obesity. COX-2 activity is in turn upregulated by ROS.
Asunto(s)
Ciclooxigenasa 2/fisiología , Obesidad/enzimología , Estrés Oxidativo , Acetilcolina/farmacología , Animales , Ciclooxigenasa 1/metabolismo , Endotelio Vascular/enzimología , Endotelio Vascular/fisiopatología , Riñón/irrigación sanguínea , Masculino , Proteínas de la Membrana/metabolismo , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa de Tipo III/metabolismo , Obesidad/fisiopatología , Ratas Zucker , Especies Reactivas de Oxígeno/metabolismo , Arteria Renal/enzimología , Arteria Renal/fisiopatología , S-Nitroso-N-Acetilpenicilamina/farmacología , Vasodilatación , Vasodilatadores/farmacologíaRESUMEN
According to previous observations nitric oxide (NO), as well as an unknown nature mediator are involved in the inhibitory neurotransmission to the intravesical ureter. This study investigates the hydrogen sulfide (H2S) role in the neurogenic relaxation of the pig intravesical ureter. We have performed western blot and immunohistochemistry to study the expression of the H2S synthesis enzymes cystathionine γ-lyase (CSE) and cystathionine ß-synthase (CBS), measurement of enzymatic production of H2S and myographic studies for isometric force recording. Immunohistochemical assays showed a high CSE expression in the intravesical ureter muscular layer, as well as a strong CSE-immunoreactivity within nerve fibres distributed along smooth muscle bundles. CBS expression, however, was not consistently observed. On ureteral strips precontracted with thromboxane A2 analogue U46619, electrical field stimulation (EFS) and the H2S donor P-(4-methoxyphenyl)-P-4-morpholinylphosphinodithioic acid (GYY4137) evoked frequency- and concentration-dependent relaxations. CSE inhibition with DL-propargylglycine (PPG) reduced EFS-elicited responses and a combined blockade of both CSE and NO synthase (NOS) with, respectively, PPG and NG-nitro-L-arginine (L-NOARG), greatly reduced such relaxations. Endogenous H2S production rate was reduced by PPG, rescued by addition of GYY4137 and was not changed by L-NOARG. EFS and GYY4137 relaxations were also reduced by capsaicin-sensitive primary afferents (CSPA) desensitization with capsaicin and blockade of ATP-dependent K+ (KATP) channels, transient receptor potential A1 (TRPA1), transient receptor potential vanilloid 1 (TRPV1), vasoactive intestinal peptide/pituitary adenylyl cyclase-activating polypeptide (VIP/PACAP) and calcitonin gene-related peptide (CGRP) receptors with glibenclamide, HC030031, AMG9810, PACAP6-38 and CGRP8-37, respectively. These results suggest that H2S, synthesized by CSE, is involved in the inhibitory neurotransmission to the pig intravesical ureter, through an NO-independent pathway, producing smooth muscle relaxation via KATP channel activation. H2S also promotes the release of inhibitory neuropeptides, as PACAP 38 and/or CGRP from CSPA through TRPA1, TRPV1 and related ion channel activation.
Asunto(s)
Sulfuro de Hidrógeno/metabolismo , Transmisión Sináptica , Uréter/enzimología , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacología , Animales , Cistationina betasintasa/metabolismo , Cistationina gamma-Liasa/metabolismo , Femenino , Masculino , Morfolinas/farmacología , Músculo Liso/enzimología , Neuropéptidos/metabolismo , Compuestos Organotiofosforados/farmacología , Porcinos , Transmisión Sináptica/efectos de los fármacos , Uréter/citología , Vasoconstrictores/farmacologíaRESUMEN
OBJECTIVE: Peripheral arterial disease is one of the macrovascular complications of type 2 diabetes mellitus. This study addresses femoral artery regulation in a prediabetic model of obese Zucker rats (OZR) by examining cross-talk between endothelial and neural factors. METHODS AND RESULTS: Arterial preparations from lean (LZR) and OZR were subjected to electrical field stimulation (EFS) on basal tone. Nitric oxide synthase (NOS) and cyclooxygenase (COX) isoform expression patterns were determined by immunohistochemical labelling and Western blotting. Results indicate significantly reduced noradrenergic contractions in preparations from OZR compared with those of LZR. Functional inhibition of endothelial NOS (eNOS) indicated a predominant role of this isoform in LZR and its modified activity in OZR. Neural (nNOS) and inducible NOS (iNOS) were activated and their expression was higher in femoral arteries from OZR. Neurotransmission modulated by large-conductance Ca2+-activated (BKCa) or voltage-dependent (KV) K+ channels did not seem compromised in the obese animals. Endothelial COX-1 and COX-2 were expressed in LZR and an additional adventitial location of COX-2 was also observed in OZR, explaining the higher COX-2 protein levels detected in this group. Prostanoids derived from both isoforms helped maintain vasoconstriction in LZR while in OZR only COX-2 was active. Superoxide anion inhibition reduced contractions in endothelium-intact arteries from OZR. CONCLUSIONS: Endothelial dysfunction led to reduced neurogenic vasoconstriction in femoral arteries from OZR. In a setting of obesity, NO-dependent nNOS and iNOS dilation activity could be an alternative mechanism to offset COX-2- and reactive oxygen species-mediated vasoconstriction, along with impaired endothelial NO relaxation.
Asunto(s)
Arteria Femoral/fisiopatología , Neuronas/metabolismo , Óxido Nítrico Sintasa/metabolismo , Obesidad/enzimología , Obesidad/fisiopatología , Prostaglandina-Endoperóxido Sintasas/metabolismo , Vasoconstricción , Animales , Modelos Animales de Enfermedad , Estimulación Eléctrica , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Isoenzimas/metabolismo , Masculino , Canales de Potasio/metabolismo , Ratas Zucker , Superóxidos/metabolismoRESUMEN
INTRODUCTION: Phosphodiesterase type 5 (PDE5) inhibitors act as effective drugs for the treatment of lower urinary tract symptom (LUTS). There is a poor information, however, about the role of the PDE4 inhibitors on the bladder outflow region contractility. AIM: To investigate PDE4 expression and the relaxation induced by the PDE4 inhibitor rolipram versus that induced by the PDE5 blockers sildenafil and vardenafil, in the pig and human bladder neck. METHODS: Immunohistochemistry for PDE4 expression, myographs for isometric force recordings and fura-2 fluorescence for simultaneous measurements of intracellular Ca2+ concentration ([Ca2+]i ) and tension for rolipram in bladder neck samples were used. MAIN OUTCOME MEASURES: PDE4 expression and relaxations to PDE4 and PDE5 inhibitors and simultaneous measurements of [Ca2+]i and tension. RESULTS: PDE4 expression was observed widely distributed in the smooth muscle layer of the pig and human bladder neck. On urothelium-denuded phenylephrine (PhE)-precontracted strips of pig and human, rolipram, sildenafil and vardenafil produced concentration-dependent relaxations with the following order of potency: rolipram> > sildenafil>vardenafil. In pig, the adenylyl cyclase activator forskolin potentiated rolipram-elicited relaxation, whereas protein kinase A (PKA) blockade reduced such effect. On potassium-enriched physiological saline solution (KPSS)-precontracted strips, rolipram evoked a lower relaxation than that obtained on PhE-stimulated preparations. Inhibition of large (BKCa ) and intermediate (IKCa ) conductance Ca2+ -activated K+ channels, neuronal voltage-gated Ca2+ channels, nitric oxide (NO) and hydrogen sulfide (H2 S) synthases reduced rolipram responses. Rolipram inhibited the contractions induced by PhE without reducing the PhE-evoked [Ca2+]i increase. CONCLUSIONS: PDE4 is present in the pig and human bladder neck smooth muscle, where rolipram exerts a much more potent relaxation than that elicited by PDE5 inhibitors. In pig, rolipram-induced response is produced through the PKA pathway involving BKCa and IKCa channel activation and [Ca2+]i desensitization-dependent mechanisms, this relaxation also being due to neuronal NO and H2S release.
Asunto(s)
Inhibidores de Fosfodiesterasa 4/farmacología , Rolipram/farmacología , Vejiga Urinaria/efectos de los fármacos , Adulto , Animales , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 5/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Imidazoles/farmacología , Masculino , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/metabolismo , Fenilefrina/farmacología , Inhibidores de Fosfodiesterasa 5/farmacología , Piperazinas/farmacología , Purinas/farmacología , Transducción de Señal/fisiología , Citrato de Sildenafil , Sulfonas/farmacología , Sus scrofa , Triazinas/farmacología , Vejiga Urinaria/metabolismo , Urotelio/metabolismo , Diclorhidrato de VardenafilRESUMEN
INTRODUCTION: Endothelin 1 (ET-1) levels and receptors are up-regulated in the erectile tissue of diabetic patients and animal models of erectile dysfunction (ED). AIM: The present study assessed the role of ET-1 receptors in the impaired adrenergic vasoconstriction and nitrergic relaxation of penile arteries from a rat model of insulin resistance. METHODS: The effect of ET receptor antagonists was evaluated on the contractile responses to electrical field stimulation (EFS) of penile arteries from obese Zucker rats (OZRs) compared with lean Zucker rats (LZRs). ET receptor expression was determined by immunohistochemistry. MAIN OUTCOME MEASURES: Changes in neural nitrergic relaxation and adrenergic vasoconstriction and the expression of ET receptors in perivascular nerves were assessed. RESULTS: ET-1 (10(-10) M) enhanced EFS-induced vasoconstriction, and treatment with the adrenergic neurotoxin guanethidine reduced the contractions induced by ET-1 in penile arteries from both LZRs and OZRs, thus supporting the hypothesis that ET-1 releases noradrenaline from adrenergic nerves. ET-1 antagonized neural nitric oxide (NO)-mediated relaxant responses in LZR arteries, antagonizing relaxations induced by the NO donor S-nitroso-N-acetylpenicillamine to a larger extent in arteries from OZRs. ET(A) and ET(B) receptors were expressed in perivascular fibers colocalized with the neuronal marker protein gene product 9.5 in penile arteries from OZRs. The ET(A) receptor antagonist BQ-123 reversed the enhancing effect of ET-1 on the vasoconstriction elicited by EFS and the ET-1-induced inhibition of nitrergic relaxations in LZRs, restoring them to control levels in penile arteries of OZRs. CONCLUSIONS: ET-1 enhances adrenergic vasoconstriction through presynaptic ET(A) receptors and antagonizes neural NO-mediated relaxation through postsynaptic smooth muscle ET(A) receptors in penile arteries from OZRs, which likely contributes to the augmented vasoconstriction and blunted nitrergic relaxation of erectile tissue under conditions of insulin resistance.
Asunto(s)
Resistencia a la Insulina/fisiología , Pene/irrigación sanguínea , Receptor de Endotelina A/fisiología , Vasoconstricción/fisiología , Adrenérgicos/farmacología , Animales , Arterias/fisiología , Antagonistas de los Receptores de la Endotelina A , Endotelina-1/metabolismo , Endotelina-1/fisiología , Disfunción Eréctil/fisiopatología , Guanetidina/farmacología , Insulina/farmacología , Masculino , Relajación Muscular/fisiología , Músculo Liso Vascular/fisiología , Neurotoxinas/farmacología , Óxido Nítrico/fisiología , Obesidad/fisiopatología , Erección Peniana/efectos de los fármacos , Péptidos Cíclicos/farmacología , Ratas Zucker , Vasodilatación/fisiología , Vasodilatadores/farmacologíaRESUMEN
AIMS: The current study investigates the role played by bradykinin (BK) receptors in the contractility to the pig bladder neck smooth muscle. METHODS: Bladder neck strips were mounted in myographs for isometric force recordings and BK receptors expression was also determined by immunohistochemistry. RESULTS: B2 receptor expression was observed in the muscular layer and urothelium whereas B1 expression was consistent detected in urothelium. A strong B2 immunoreactivity was also observed within nerve fibers among smooth muscle bundles. On urothelium-denuded preparations basal tone, BK induced concentration-dependent contractions which were reduced in urothelium-intact samples, by extracellular Ca(2+) removal and by blockade of B2 receptors and voltage-gated Ca(2+) (VOC) and non-VOC channels, and increased by cyclooxygenase (COX) inhibition. On phenylephrine-precontracted denuded strips, under non-adrenergic non-cholinergic (NANC) conditions, electrical field stimulation-elicited frequency-dependent relaxations which were reduced by B2 receptor blockade. In urothelium-intact samples, the B1 receptor agonist kallidin promoted concentration-dependent relaxations which were reduced by blockade of B1 receptors, COX, COX-1 and large-conductance Ca(2+) -activated K(+) (BKCa ) channels and abolished in urothelium-denuded samples and in K(+) -enriched physiological saline solution-precontracted strips. CONCLUSIONS: These results suggest that BK produces contraction of pig bladder neck via smooth muscle B2 receptors coupled to extracellular Ca(2+) entry via VOC and non-VOC channels with a minor role for intracellular Ca(2+) mobilization. Facilitatory neuronal B2 receptors modulating NANC inhibitory neurotransmission and urothelial B1 receptors producing relaxation via the COX-1 pathway and BKCa channel opening are also demonstrated. Neurourol. Urodynam. 33:558-565, 2014. © 2013 Wiley Periodicals, Inc.
Asunto(s)
Calcio/metabolismo , Contracción Muscular/fisiología , Relajación Muscular/fisiología , Músculo Liso/metabolismo , Receptor de Bradiquinina B1/metabolismo , Receptor de Bradiquinina B2/metabolismo , Vejiga Urinaria/metabolismo , Urotelio/metabolismo , Animales , Bradiquinina/farmacología , Antagonistas de los Receptores de Bradiquinina/farmacología , Canales de Calcio/metabolismo , Ciclooxigenasa 1/metabolismo , Inmunohistoquímica , Técnicas In Vitro , Contracción Isométrica/efectos de los fármacos , Contracción Isométrica/fisiología , Canales de Potasio de Gran Conductancia Activados por el Calcio/metabolismo , Contracción Muscular/efectos de los fármacos , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Prostaglandina-Endoperóxido Sintasas/metabolismo , Receptor de Bradiquinina B1/fisiología , Receptor de Bradiquinina B2/fisiología , Transducción de Señal , Porcinos , Vejiga Urinaria/efectos de los fármacos , Vejiga Urinaria/fisiología , Urotelio/efectos de los fármacosRESUMEN
Progesterone increases bladder capacity and improves the bladder compliance by its relaxant action on the detrusor. A poor information, however, exists concerning to the role of this steroid hormone on the bladder outflow region contractility. This study investigates the progesterone-induced action on the smooth muscle tension of the pig bladder neck. To this aim, urothelium-denuded bladder neck strips were mounted in myographs for isometric force recordings and for simultaneous measurements of intracellular Ca(2+) concentration ([Ca(2+)]i) and tension. On phenylephrine (PhE)-precontracted strips, progesterone produced concentration-dependent relaxations only at high pharmacological concentrations. The blockade of progesterone receptors, nitric oxide (NO) synthase, guanylyl cyclase, large conductance Ca(2+)-activated K(+) (BKCa) or ATP-dependent K(+) (KATP) channels reduced the progesterone relaxations. The presence of the urothelium and the inhibition of cyclooxygenase (COX), intermediate- and small-conductance Ca(2+)-activated K(+) channels failed to modify these responses. In Ca(2+)-free potassium rich physiological saline solution, progesterone inhibited the contraction to CaCl2 and to the L-type voltage-operated Ca(2+) (VOC) channel activator BAY-K 8644. Relaxation induced by progesterone was accompanied by simultaneous decreases in smooth muscle [Ca(2+)]i. These results suggest that progesterone promotes relaxation of pig bladder neck through smooth muscle progesterone receptors via cGMP/NO pathway and involving the activation of BKCa and KATP channels and inhibition of the extracellular Ca(2+) entry through L-type VOC channels.