RESUMEN
Small ruminant production is a common agricultural activity worldwide. However, studies on the fungal microbiota of these animals are scarce. Therefore, this study aimed at isolating yeasts from goats and sheep and evaluating the antifungal susceptibility of the recovered Candida albicans. A total of 120 animals from farms in Ceará State, Brazil, were assessed in this study. The samples were collected from nasal, oral and rectal cavities with sterile swabs. Candida spp., Trichosporon spp. and Rhodotorula spp. were isolated from small ruminants. Resistance to three azole drugs was observed in C. albicans. In summary, Candida spp. were predominantly observed as part of the microbiota of the nasal, oral and rectal cavities of small ruminants, including azole-resistant strains of C. albicans.
Asunto(s)
Antifúngicos/farmacología , Azoles/farmacología , Candida albicans/aislamiento & purificación , Farmacorresistencia Fúngica , Cabras/microbiología , Ovinos/microbiología , Animales , Brasil , Boca/microbiología , Cavidad Nasal/microbiología , Recto/microbiología , Rhodotorula/aislamiento & purificación , Trichosporon/aislamiento & purificaciónRESUMEN
This study aimed at evaluating the in vitro antifungal susceptibility of Candida albicans isolates obtained during necropsy of a wild Brazilian porcupine and the mechanism of azole resistance. Initially, we investigated the in vitro susceptibility of the three isolates to amphotericin B, caspofungin, fluconazole, itraconazole, ketoconazole and voriconazole. Afterwards, three sub-inhibitory concentrations (47, 21 and 12 mg/l) of promethazine, an efflux pump inhibitor, were tested in combination with the antifungal drugs in order to evaluate the role of these pumps in the development of antifungal resistance. In addition, the three isolates were submitted to RAPD-PCR and M13-fingerprinting analyses. The minimum inhibitory concentrations (MICs) obtained with the isolates were 1, 0.03125, 250, 125, 8 and 250 mg/l for amphotericin B, caspofungin, fluconazole, itraconazole, ketoconazole and voriconazole, respectively, and the isolates were found to be resistant to all tested azoles. The addition of the three subinhibitory concentrations of promethazine resulted in statistically significant (P < 0.05) reductions in the MICs for all tested drugs, with decreases to azoles being statistically greater than those for amphotericin B and caspofungin (P < 0.05). The molecular analyses showed a genetic similarity among the three tested isolates, suggesting the occurrence of candidemia in the studied animal. These findings highlight the importance of monitoring antifungal susceptibility of Candida spp. from veterinary sources, especially as they may indicate the occurrence of primary azole resistance even in wild animals.
Asunto(s)
Antifúngicos/farmacología , Azoles/farmacología , Candida albicans/efectos de los fármacos , Candida albicans/aislamiento & purificación , Farmacorresistencia Fúngica , Puercoespines/microbiología , Animales , Brasil , Candida albicans/clasificación , Candida albicans/genética , Pruebas de Sensibilidad Microbiana , Tipificación Molecular , Técnicas de Tipificación Micológica , Técnica del ADN Polimorfo Amplificado AleatorioRESUMEN
The Cryptococcus neoformans species complex contains the most important agents of fungal meningoencephalitis. Therapeutic choices are limited and issues related to toxicity and resistance to antifungals have been described. The present study evaluated the inhibitory effect of the antifolate combinations sulfamethoxazole-trimethoprim (SMX/TMP) and sulfadiazine-pyrimethamine (SDZ/PYR) against planktonic cells and biofilms of C. neoformans and C. gattii. The influence of the antifolate combinations on the amphotericin minimum inhibitory concentration (MIC) of planktonic cells was also investigated. In addition, the effect of these combinations on the cellular ergosterol content of planktonic cells was studied. Strains of C. neoformans (n = 15) and C. gattii (n = 15) obtained from environmental or clinical sources were evaluated by the broth microdilution method. SMX/TMP and SDZ/PYR showed antifungal activity against free living cells and sessile cells of Cryptococcus spp. Moreover, planktonic cells showed increased susceptibility to amphotericin B after pre-incubation with sub-inhibitory concentrations of SMX/TMP or SDZ/PYR. The drug combinations SMX/TMP and SDZ/PYR were able to prevent the biofilm formation and showed inhibitory effect against mature biofilms of both species. Additionally, the study showed that antifolate drugs reduced the ergosterol content in C. neoformans and C. gattii planktonic cells. Our results highlight the antifungal potential of antifolate drugs.
Asunto(s)
Anfotericina B/metabolismo , Antifúngicos/metabolismo , Biopelículas/efectos de los fármacos , Cryptococcus gattii/efectos de los fármacos , Cryptococcus neoformans/efectos de los fármacos , Antagonistas del Ácido Fólico/metabolismo , Criptococosis/microbiología , Cryptococcus gattii/fisiología , Cryptococcus neoformans/aislamiento & purificación , Cryptococcus neoformans/fisiología , Combinación de Medicamentos , Microbiología Ambiental , Humanos , Pruebas de Sensibilidad Microbiana , Pirimetamina/metabolismo , Sulfadoxina/metabolismo , Combinación Trimetoprim y Sulfametoxazol/metabolismoRESUMEN
The effects of the protease inhibitors saquinavir, darunavir, ritonavir, and indinavir on growth inhibition, protease and phospholipase activities, as well as capsule thickness of Cryptococcus neoformans were investigated. Viral protease inhibitors did not reduce fungal growth when tested in concentrations ranging from 0.001 to 1.000 mg/L. A tendency toward increasing phospholipase activity was observed with the highest tested drug concentration in a strain-specific pattern. However, these drugs reduced protease activity as well as capsule production. Our results confirm a previous finding that antiretroviral drugs affect the production of important virulence factors of C. neoformans.
Asunto(s)
Antirretrovirales/farmacología , Cryptococcus neoformans/efectos de los fármacos , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Inhibidores de Proteasas/farmacología , Cryptococcus neoformans/enzimología , Cryptococcus neoformans/patogenicidad , Indinavir/farmacología , Ritonavir/farmacología , Saquinavir/farmacología , Factores de Virulencia/genéticaRESUMEN
Candida meningitis is a rare condition that occurs more frequently in premature infants, immunocompromised patients or patients after neurosurgery. We describe a case of a previously healthy 41-year-old man with Candida parapsilosis meningitis associated with oropharyngeal candidiasis as the first manifestation of AIDS.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , Síndrome de Inmunodeficiencia Adquirida/diagnóstico , Candida/aislamiento & purificación , Candidiasis Invasiva/diagnóstico , Candidiasis Invasiva/patología , Meningitis Fúngica/diagnóstico , Meningitis Fúngica/patología , Adulto , Candida/clasificación , Candidiasis Bucal/diagnóstico , Candidiasis Bucal/patología , ADN de Hongos/química , ADN de Hongos/genética , ADN Espaciador Ribosómico/química , ADN Espaciador Ribosómico/genética , Electroforesis en Gel de Agar , Humanos , Masculino , Reacción en Cadena de la PolimerasaRESUMEN
The purpose of this study was to biomonitor metropolitan areas of Porto Alegre (Brazil) for PAHs associated with atmospheric particles and check their effects on the DNA of the land mollusk Helix aspersa. The sampling sites are located in an urban area with heavy traffic: (i) Canoas, (ii) Sapucaia do Sul, and (iii) FIERGS/Porto Alegre. The samples were collected during a continuous period of 24 hours during 15 days using Stacked Filter Units (SFU) on polycarbonate filters (two separated size fractions: PM(10-2.5) and PM(< 2.5)). The concentrations of 16 major PAHs were determined according to EPA. Comet assay on H. aspersa hemolymph cells was chosen for genotoxicity evaluation. This evaluation shows that, in general, the smaller PM-size fractions (PM(< 2.5)) have the highest genotoxicity and contain higher concentrations of extractable organic matter. In addition, associations between chemical characteristics and PM carcinogenicity tend to be stronger for the smaller PM-size fractions.
Asunto(s)
Contaminantes Atmosféricos/toxicidad , Ecotoxicología/métodos , Hidrocarburos Policíclicos Aromáticos/toxicidad , Salud Urbana , Animales , Brasil , Ensayo Cometa , ADN/sangre , Monitoreo del Ambiente/métodos , Caracoles Helix , Hemolinfa , Humanos , Material Particulado , Emisiones de VehículosRESUMEN
BACKGROUND AND PURPOSE: Phosphodiesterase type-5 (PDE5) inhibitors constitute a novel and important therapeutic option for the treatment of pulmonary hypertension. The effects of the PDE5 inhibitors sildenafil, tadalafil and vardenafil on rabbit isolated pulmonary artery ring preparations and on intracellular Ca2+ concentration of thrombin-stimulated human platelets were investigated. EXPERIMENTAL APPROACH: Rabbit pulmonary artery rings were mounted in 10 mL organ bath containing Krebs solution. Tissues were connected to force-displacement transducers, and changes in isometric force were recorded. Ca2+ flux in human washed platelets was measured. KEY RESULTS: Sildenafil, tadalafil and vardenafil (0.0001-10 microM) concentration-dependently relaxed endothelium-intact and endothelium-denuded pulmonary artery rings. Endothelium denudation caused rightward shifts in the concentration-response curves to sildenafil, tadalafil and vardenafil (9-, 12- and 123-fold, respectively). Incubation with N(omega)-nitro-L-arginine methyl ester (100 microM) or ODQ (1H-[1,2,4] oxadiazolo [4,3,-a]quinoxalin-1-one) (10 microM) caused similar reductions of PDE5-induced vasorelaxations in intact rings. Sildenafil and tadalafil did not affect the phenylephrine-induced contractions, whereas vardenafil reduced the maximal responses, and shifted the phenylephrine-induced contraction curves to the right in endothelium-denuded rings (5- and 19-fold for 1 and 10 microM, respectively). Vardenafil (but neither sildenafil nor tadalafil) caused a marked rightward shift and a decrease of maximal contractile response to CaCl2. Vardenafil, but neither sildenafil nor tadalafil, significantly reduced the Ca2+ mobilization and Ca2+ influx in thrombin-stimulated washed platelets. CONCLUSIONS AND IMPLICATIONS: Our results indicate that vardenafil, in contrast to sildenafil or tadalafil, also blocked Ca2+ fluxes, thus enhancing its vasorelaxation of the pulmonary artery.
Asunto(s)
Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio/efectos de los fármacos , Calcio/metabolismo , Inhibidores de Fosfodiesterasa/farmacología , Animales , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Bloqueadores de los Canales de Calcio/administración & dosificación , Canales de Calcio/metabolismo , Carbolinas/administración & dosificación , Carbolinas/farmacología , Relación Dosis-Respuesta a Droga , Endotelio Vascular/metabolismo , Humanos , Imidazoles/administración & dosificación , Imidazoles/farmacología , Técnicas In Vitro , Masculino , Inhibidores de Fosfodiesterasa/administración & dosificación , Piperazinas/administración & dosificación , Piperazinas/farmacología , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/metabolismo , Purinas/administración & dosificación , Purinas/farmacología , Conejos , Citrato de Sildenafil , Sulfonas/administración & dosificación , Sulfonas/farmacología , Tadalafilo , Triazinas/administración & dosificación , Triazinas/farmacología , Diclorhidrato de Vardenafil , Vasodilatación/efectos de los fármacosRESUMEN
The aim of this work was to evaluate the influence of run training on the responsiveness of corpus cavernosum (CC) from rats made hypertensive by treatment with nitric oxide (NO) synthesis inhibitor. Wistar rats were divided into sedentary control (C-SD), exercise training (C-TR), N(omega)-nitro-L-arginine methyl ester (L-NAME) sedentary (LN-SD) and L-NAME trained (LN-TR) groups. The run training program consisted in 8 weeks in a treadmill, 5 days/week, each session lasted 60 min. L-NAME treatment (2 and 10 mg/rat/day) started after 4 weeks of prior physical conditioning and lasted 4 weeks. Concentration-response curves were obtained for acetylcholine (ACh), sodium nitroprusside (SNP), sildenafil and BAY 41-2272. The effect of electrical field stimulation (EFS) on the relaxations responses of CC was evaluated. Run training prevented the arterial hypertension induced by L-NAME treatment (LN-SD: 135+/-2 and 141+/-2 mm Hg for both doses of L-NAME) compared to LN-SD groups (154+/-1 and 175+/-2 mm Hg, for 2 and 10 mg of L-NAME, respectively). Run training produced an increase in the maximal responses (E(max)) of CC for ACh (C-SD: 47+/-3; C-TR: 52+/-1; and LN-TR: 53+/-3%) and SNP (C-SD: 89+/-1; C-TR: 98+/-1; and LN-TR: 95+/-1%). Both potency and E(max) for ACh were reduced in a dose of 10 mg of L-NAME, and run training restored the reduction of E(max) for ACh. No changes were found for BAY 41-2271 and sildenafil. Relaxing responses to EFS was reduced by L-NAME treatment that was restored by prior physical conditioning. In conclusion, our study shows a beneficial effect of prior physical conditioning on the impaired CC relaxing responses in rats made hypertensive by chronic NO blockade.
Asunto(s)
Hipertensión/fisiopatología , Relajación Muscular/efectos de los fármacos , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/metabolismo , Pene/fisiología , Acetilcolina/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Inhibidores Enzimáticos/farmacología , Hipertensión/inducido químicamente , Hipertensión/tratamiento farmacológico , Técnicas In Vitro , Masculino , Óxido Nítrico Sintasa/antagonistas & inhibidores , Nitroprusiato/farmacología , Pene/efectos de los fármacos , Condicionamiento Físico Animal , Piperazinas/farmacología , Purinas/farmacología , Pirazoles/farmacología , Piridinas/farmacología , Ratas , Ratas Wistar , Citrato de Sildenafil , Sulfonas/farmacologíaRESUMEN
The effects of the Brazilian herbal medicine Catuama and each of its plant constituents (Paullinia cupana, Trichilia catigua, Zingiber officinalis and Ptychopetalum olacoides) were investigated on rabbit corpus cavernosum (RbCC) using a bioassay cascade. Catuama caused short-lived and dose-dependent relaxations (11% +/- 7%, 26% +/- 5% and 82% +/- 9%, at doses of 1, 3 and 10 mg, respectively). Neither the nitric oxide synthesis inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME; 10 microM) nor the soluble guanylate cyclase inhibitor ODQ (10 microM) significantly affected the Catuama-induced relaxations. Similarly, the selective ATP-dependent K(+) channel (K(ATP)) blocker glibenclamide (10 microM), the muscarinic receptor antagonist atropine (1 microM) and the voltage-dependent Na(+) channel blocker tetrodotoxin (1 microM) all failed to affect significantly the Catuama-induced relaxations. These results indicate that the relaxations induced by Catuama involve neither nitric oxide release nor K(ATP) channel activation. The extracts of P. cupana, Z. officinalis and P. olacoides caused short-lived and dose-dependent RbCC relaxations, whereas T. catigua evoked long-lasting relaxations which were occasionally preceded by a brief contractile effect. The extract of P. cupana was the most active in relaxing RbCC strips. The relaxations induced by all extracts were not significantly affected by L-NAME (10 microM). The infusion of ODQ (10 microM) had no significant effect on the P. cupana- and Z. officinalis-induced relaxations but reduced by >50% (p < 0.05) those evoked by P. olacoides and T. catigua. Incubations of RbCC with Catuama(10 mg/mL for 0.25 to 5 min) caused increases of cAMP levels (143% increase at 5 min of incubation). Incubations of RbCC with P. cupana extract (1 mg/mL) increased the cAMP levels by 200% whereas higher doses (10 and 100 mg/mL) caused smaller increases in the nucleotide levels (150% and 89%, respectively). The extracts of Z. officinalis and P. olacoides (same doses) caused smaller increases of the cAMP levels compared with the P. cupana extract, whereas T. catigua (1-100 mg) did not increase the levels of this nucleotide above the basal values. Our results show that of the four extracts assayed, P. cupana was the most effective, indicating that it is the main extract responsible for the relaxing effect of Catuama on rabbit cavernosal tissue.
Asunto(s)
Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Extractos Vegetales/farmacología , Plantas Medicinales , Rosales , Estómago/efectos de los fármacos , Animales , AMP Cíclico/metabolismo , Relación Dosis-Respuesta a Droga , Masculino , Extractos Vegetales/administración & dosificación , ConejosRESUMEN
OBJECTIVES: To examine the effects of Tityus serrulatus scorpion venom (TSV) on human corpus cavernosum (HCC) using a bioassay cascade. Priapism is occasionally observed in scorpion envenomation, mostly in children. METHODS: HCC strips were suspended in a cascade system and superfused with aerated and warmed Krebs' solution at 5 mL/min. Noradrenaline (3 micromol/L) was infused to induce a submaximal contraction of the HCC strips. The release of cyclooxygenase products was prevented by infusing indomethacin (6 micromol/L). RESULTS: N(omega)-nitro-L-arginine methyl ester (10 micromol/L; n = 10) increased the tone of the preparations and significantly reduced (P <0.01) the acetylcholine (ACh) and TSV-induced relaxations. Subsequent infusion of L-arginine (300 micromol/L) partially reversed the increased tone and significantly restored the relaxations induced by TSV and ACh (P <0.01). The soluble guanylyl cyclase inhibitor ODQ (10 micromol/L; n = 8) markedly reduced (P <0.01) the relaxations induced by TSV, ACh, glyceryl trinitrate, and bradykinin. 7-Nitroindazole (10 micromol/L; n = 8) inhibited the relaxations induced by TSV by 84% (P <0.01) and also caused small, but significant, reductions in the ACh and bradykinin-induced HCC relaxations (P <0.05). Atropine (1 micromol/L; n = 6) abolished the relaxations evoked by ACh (P <0.01), but had no effect on those elicited by TSV. Tetrodotoxin (1 micromol/L; n = 6) abolished the relaxations induced by TSV (P <0.01) and also reversed the established TSV-induced relaxation (n = 4). CONCLUSIONS: Our results indicate that TSV relaxes HCC through the release of nitric oxide from nonadrenergic, noncholinergic (NANC) nerves. The elucidation of the mechanism responsible for the TSV-induced relaxations might be useful for a better understanding of the development of priapism in cases of scorpion envenomation.
Asunto(s)
Erección Peniana/efectos de los fármacos , Erección Peniana/fisiología , Pene/fisiología , Acetilcolina/farmacología , Adulto , Arginina/farmacología , Atropina/farmacología , Bradiquinina/farmacología , Inhibidores de la Ciclooxigenasa/farmacología , Histamina/farmacología , Humanos , Técnicas In Vitro , Indometacina/farmacología , Masculino , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa/farmacología , Norepinefrina/farmacología , Pene/inervación , Priapismo/inducido químicamente , Priapismo/fisiopatología , Venenos de Escorpión , Tetrodotoxina/farmacologíaRESUMEN
In this study, we have investigated the relaxing effects of both Androctonus australis venom (AAV) and Buthotus judaicus venom (BJV) on the rabbit corpus cavernosum (RbCC) smooth muscle strips. The RbCC strips were mounted in a cascade system and superfused with warmed and gassed Krebs solution. The nitric oxide (NO) synthesis inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME, 10microM), but not D-NAME (10microM), significantly inhibited the RbCC relaxations induced by acetylcholine (ACh, 0.6nmol), AAV (30microg) and BJV (30microg). Subsequent infusion of L-arginine (300microM), but not of D-arginine (300microM), partially restored the relaxations evoked by these agents. The brain NO synthase inhibitor 7-nitroindazole (7-NI, 10microM) also inhibited the relaxant responses elicited by the scorpion venoms. The guanylyl cyclase inhibitors methylene blue (MB, 30microM) and 1H-[1,2,4] oxadiazolo [4,3,-alquinoxalin-1-one] (ODQ, 10microM) virtually abolished the relaxations induced by either AAV or BJV. The infusion of muscarinic receptor antagonists such as scopolamine and atropine (1microM, each) completely abolished the ACh-induced relaxations but had no effect on those evoked by the scorpion venoms. The Na(+) channel blocker tetrodotoxin (1microM) prevented the relaxations evoked by both AAV and BJV. Thus, NO released from nitrergic nerve fibres mediates the relaxations elicited by AAV and BJV in the rabbit cavernosal tissue.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Antagonistas Muscarínicos/farmacología , Relajación Muscular/efectos de los fármacos , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/fisiología , Venenos de Escorpión/farmacología , Acetilcolina/farmacología , Análisis de Varianza , Animales , Atropina/farmacología , Interacciones Farmacológicas , Indazoles/farmacología , Masculino , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , NG-Nitroarginina Metil Éster/antagonistas & inhibidores , Óxido Nítrico/metabolismo , Pene/efectos de los fármacos , Conejos , Escopolamina/farmacología , Venenos de Escorpión/antagonistas & inhibidores , Venenos de Escorpión/enzimología , Estereoisomerismo , Tetrodotoxina/farmacologíaRESUMEN
Myelomeningocele occurs in 0.4 for 1000 neonates and is associated with hydrocephalus in 85-90%, and reports on cognition are sparsely found in literature. Forty five children with treated hydrocephalus and myelomeningocele were studied in regard of IQ, and statistically correlated to functional motor level, age of the first shunt, number of revisions of shunt, infection of the shunt and circumference of the head. The medium age was of 7.5 years (3-15 years), 16 males and 29 females. Three (6.6%) had a IQ score > 110, 11 (24.4%) had a score between 100-110, 8 between 85-100 (17.7%), 16 (35.5%) between 85-100 (17.7%) and 7 (15.5%) between 50-70. IQ directly correlated with motor level, having better cognitive results the children with minor functional motor disabilities. Cognition was best in children operated until the seven day of life (t 0.0099), with progressive worse results in children operated after the first month of life, no significance was observed in children operated in the period 7 to 31 days (t 0.1013). Worse results were observed in the group of patients with infection of shunts (t 0.0146). Results were progressively worse with reoperations. The best results in relation of the circumference of the head were seen with children in the medium range (t 0.0115); intermediate results were seen in patients between the medium range and-1SD (t 0.00130) and medium range and +1SD. The worse results were seen in patients at the extremes of > 1SD (t 0.0269) and < ISD (t 0.0042). According to cognitive results the surgical treatment of hydrocephalus have to be done until the first month of life, avoiding reoperations and infections that have unfavorable impact in IQ.
Asunto(s)
Cognición , Hidrocefalia/cirugía , Inteligencia , Meningomielocele/cirugía , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , Pruebas PsicológicasRESUMEN
The influence of nitric oxide (NO) on eosinophil infiltration into the airways was investigated in rats actively sensitized with ovalbumin. The animals were treated chronically with the NO synthase inhibitor, N omega-Nitro-L-arginine methyl ester (L-NAME; 75 mumol rat-1 day-1), for 4 weeks. Bronchoalveolar lavage was performed at 6, 24, 48 and 72 h after intratracheal injection of ovalbumin. Intratracheal challenge of the sensitized rats with ovalbumin caused a significant increase in total leucocyte infiltration in bronchoalveolar lavage fluid both 24 and 48 h post-ovalbumin injection. Neutrophils and eosinophils peaked, respectively, at 24 h (29%) and 48 h (30%) in bronchoalveolar lavage fluid whereas the mononuclear cell did not differ significantly from the counts in non-sensitized rats at any time. At both 6 and 24 h post-ovalbumin injection, the chronic treatment of the animals with L-NAME affected neither the total nor the differential leucocyte content. However, at 48 h post-ovalbumin challenge, the total cell count was reduced by approximately 48% in the L-NAME-treated animals and this was associated with a marked inhibition (81%) of the eosinophil influx. Histological examination of the lungs from these animals (48 h post-ovalbumin challenge) also showed a prominent reduction (69.5%; P < 0.05) of the eosinophil infiltration in the respiratory segments. Our results demonstrate that NO plays a pivotal role in the eosinophil infiltration in airways of actively sensitized rats.
Asunto(s)
Asma/fisiopatología , Inhibidores Enzimáticos/farmacología , Eosinófilos/patología , Óxido Nítrico/fisiología , Ovalbúmina/farmacología , Animales , Asma/inducido químicamente , Asma/inmunología , Líquido del Lavado Bronquioalveolar/citología , Líquido del Lavado Bronquioalveolar/inmunología , Inhibidores Enzimáticos/inmunología , Eosinófilos/efectos de los fármacos , Eosinófilos/inmunología , Histocitoquímica , Pulmón/efectos de los fármacos , Pulmón/inmunología , Pulmón/patología , Masculino , NG-Nitroarginina Metil Éster/farmacología , Ovalbúmina/inmunología , Ratas , Ratas WistarRESUMEN
OBJECTIVE: To characterize the kinin receptor subtype involved in the relaxation of human isolated corpus cavernosum (HCC) induced by bradykinin (BK), Lys-bradykinin (Lys-BK), Met-Lys-bradykinin (Met-Lys-BK) and des-Arg9-bradykinin, and to investigate whether the kinin-induced relaxation of HCC results from the stimulation of nonadrenergic, noncholinergic (NANC) neurons supplying the cavernosal tissue. MATERIALS AND METHODS: Excised HCC tissues were immediately placed in Krebs solution and kept at 4 degrees C until use (never > 24 h after removal). HCC was cut in strips of approximately 2 cm, suspended in a cascade system and superfused with oxygenated and warmed Krebs solution at 5 mL/min. After equilibration for approximately 90 min, noradrenaline (3 micromol/L) was infused to induce a submaximal contraction of the HCC strips. The release of cyclo-oxygenase products was prevented by infusing indomethacin (6 micromol/L). HCC strips were calibrated by injecting a single bolus of the nitrovasodilator glyceryl trinitrate (GTN) and the sensitivity of the tissues adjusted electronically to be similar. The agonists (kinins, histamine and acetylcholine) were injected as a single bolus (up to 100 microL) and the relaxation of HCC expressed as a percentage of the submaximal relaxation induced by GTN. RESULTS: Bradykinin, Lys-BK and Met-Lys-BK significantly relaxed the HCC tissues; on a molar basis, there was no statistical difference among the degrees of relaxation induced by these peptides. The B1 kinin receptor agonist des-Arg9-bradykinin had no effect on the HCC. The infusion of the B2 kinin receptor antagonist Hoe 140 (50 nmol/L) virtually abolished the relaxation induced by BK, Lys-BK and Met-Lys-BK without affecting those induced by acetylcholine and histamine. The infusion of the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester increased the tone of the HCC tissues and significantly reduced (P < 0.01) the relaxation induced by BK (74%), Lys-BK (90%), Met-Lys-BK (87%) and acetylcholine (89%) without affecting those induced by GTN. The subsequent infusion of L-arginine (300 micromol/L) partially reversed the increased tone and significantly (P < 0.01) restored the relaxation induced by BK, Lys-BK and Met-Lys-BK. The results were similar with the novel guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,3,-alquinoxalin-1-one] which reduced by > 95% (P < 0.01) the relaxation induced by BK, Lys-BK, Met-Lys-BK, acetylcholine and GTN. The infusion of the sodium-channel blocker tetrodotoxin had no significant effect on the BK-, GTN- and acetylcholine-induced relaxation of HCC. CONCLUSION: This study clearly showed the existence of functional B2 kinin receptors in human erectile tissues that when activated lead to the release of NO and hence relaxation of the HCC tissues. As tetrodotoxin failed to affect the kinin-induced relaxation of HCC strips, it is likely that these peptides release NO from the endothelium of sinusoidal capillaries rather than from neuronal sources supplying the cavernosal tissue. Although tissue kallikreins and their components have been found in the male reproductive system, the physiopathological importance of these findings has yet to be elucidated.
Asunto(s)
Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Calidina/farmacología , Pene/efectos de los fármacos , Receptores de Bradiquinina/química , Adolescente , Antagonistas Adrenérgicos beta/farmacología , Adulto , Antagonistas de los Receptores de Bradiquinina , Inhibidores Enzimáticos/farmacología , Humanos , Masculino , Persona de Mediana Edad , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico/farmacología , Erección Peniana/efectos de los fármacos , Pene/fisiología , Receptores de Bradiquinina/efectos de los fármacosRESUMEN
1. The effect of Tityus serrulatus scorpion venom and its toxin components on the rabbit isolated corpus cavernosum was investigated by use of a bioassay cascade. 2. Tityus serrulatus venom (3-100 microg), acetylcholine (ACh; 0.3-30 nmol) and glyceryl trinitrate (GTN; 0.5-10 nmol) dose-dependently relaxed rabbit isolated corpus cavernosum preparations precontracted with noradrenaline (3 microM). The selective soluble guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3,-alquinoxalin-1-one] (ODQ; 30 microM) increased the basal tone of the rabbit isolated corpus cavernosum and abolished the relaxations induced by the agents mentioned above. Methylene blue (30 microM) also inhibited the relaxations induced by Tityus serrulatus venom but, in contrast to ODQ, the inhibition was irreversible. 3. The non-selective NO synthase (NOS) inhibitors Nomega-nitro-L-arginine methyl ester (L-NAME; 10 microM) and NG-iminoethyl-L-ornithine (L-NIO; 30 microM) also increased the tone of the rabbit isolated corpus cavernosum and markedly reduced both ACh- and Tityus serrulatus venom-induced relaxations without affecting those evoked by GTN. The inhibitory effect was reversed by infusion of L-arginine (300 microM), but not D-arginine (300 microM). The neuronal NOS inhibitor 1-(2-trifluoromethylphenyl) imidazole (TRIM, 100 microM) did not affect either the tone of the rabbit isolated corpus cavernosum or the relaxations induced by ACh, bradykinin (Bk), Tityus serrulatus venom and GTN. TRIM was approximately 1,000 times less potent than L-NAME in inhibiting rabbit cerebellar NOS in vitro, as measured by the conversion of [3H]-L-arginine to [3H]-L-citrulline. 4. The protease inhibitor aprotinin (Trasylol; 10 microg ml[-1]) and the bradykinin B2 receptor antagonist Hoe 140 (D-Arg-[Hyp3,Thi5,D-Tic7, Oic8]-BK; 50 nM) did not affect the rabbit isolated corpus cavernosum relaxations induced by Tityus serrulatus venom. The ATP-dependent K+ channel antagonist glibenclamide (10 microm) and the Ca2+-activated K+ channel antagonists apamin (0.1 microM) and charybdotoxin (0.1 microM) also failed to affect the venom-induced relaxations. Similarly, the K+ channel blocker tetraethylammonium (TEA; 10 microM) had no effect on the venom-induced relaxations. 5. Capsaicin (3 and 10 nmol) relaxed the rabbit isolated corpus cavernosum in a dose-dependent and non-tachyphylactic manner. Ruthenium red (30 microM), an inhibitor of capsaicin-induced responses, markedly reduced the relaxations caused by capsaicin, but failed to affect those induced by Tityus serrulatus venom. L-NAME (10 microM) had no effect on the capsaicin-induced relaxations of the rabbit isolated corpus cavernosum. 6. The sodium channel blocker tetrodotoxin (TTX; 1 microM) abolished the relaxations of the rabbit isolated corpus cavernosum induced by Tityus serrulatus venom without affecting those evoked by capsaicin, ACh and GTN. Tetrodotoxin (1 microM) also promptly reversed the response to the venom when infused during the relaxation phase. 7. The bioassay cascade of the toxin components purified from Tityus serrulatus venom revealed that only fractions X, XI and XII caused dose-dependent relaxations of the rabbit isolated corpus cavernosum and these were markedly reduced by either TTX (1 microM) or L-NAME (10 microM). 8. Our results indicate that Tityus serrulatus scorpion venom (and the active fractions X, XI and XII) relaxes rabbit corpus cavernosum via the release of NO. This release is specifically triggered by the activation of capsaicin-insensitive cavernosal non-adrenergic non-cholinergic (NANC) fibres, that may possibly be nitrergic neurones. Tityus serrulatus venom may therefore provide an important tool for understanding further the mechanism of NANC nitrergic nerve activation.
Asunto(s)
Óxido Nítrico/fisiología , Pene/efectos de los fármacos , Venenos de Escorpión/farmacología , Animales , Aprotinina/farmacología , Atropina/farmacología , Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Inhibidores Enzimáticos/farmacología , Técnicas In Vitro , Masculino , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/metabolismo , Pene/inervación , Pene/metabolismo , Bloqueadores de los Canales de Potasio , Conejos , Receptores Adrenérgicos/metabolismo , Receptores Colinérgicos/metabolismo , Bloqueadores de los Canales de Sodio , Tetrodotoxina/farmacologíaRESUMEN
Paw edema was induced in male Wistar rats (200-250 g) by intraplantar (ipl) administration of 2.5 micrograms endotoxin (Etx). Etx, like carrageenin, produced two distinct edema formation phases, an early phase (75 min) followed by a late phase (7 h). We showed that the edema formation in the early phase was antagonized by dipyrone (80 mg/kg, i.p.) and indomethacin (1 mg/kg, i.p.) by 52% and 55%, respectively, and that the late phase was resistant to these drugs. These results suggest that in the early phase prostaglandins appear to be involved in the process. However, the activation of the kinin cascade leading to the release of other mediators may be involved in the increase of edema in the late phase. To test this hypothesis, we investigated whether the release of nitric oxide (NO) is involved in the mechanism of endotoxin-induced rat paw edema during the late phase, using N omega-nitro-L-arginine methyl ester (L-NAME) (50 micrograms, ipl) as inhibitor of NO synthase and L-arginine (1 mg, ipl) as substrate of NO synthase. The paw edema induced by Etx was inhibited by L-NAME by 56% and increased by L-arginine by 81%. Furthermore, L-arginine given in combination with L-NAME completely reversed the inhibition of Etx-induced edema produced by L-NAME. These results support the hypothesis that in the late phase NO production is associated with the edema evoked by Etx.
Asunto(s)
Antiinflamatorios no Esteroideos/uso terapéutico , Dipirona/uso terapéutico , Edema/tratamiento farmacológico , Inhibidores Enzimáticos/uso terapéutico , NG-Nitroarginina Metil Éster/uso terapéutico , Animales , Arginina , Edema/inducido químicamente , Endotoxinas , Extremidades , Masculino , Ratas , Ratas WistarRESUMEN
Paw edema was induced in male Wistar rats (200-250 g) by intraplantar (ipl) administration of 2.5 mug endotoxin (Etx). Etx, like carrageenin, produced two distinct edema formation phases, an early phase (75 min) followed by a late phase (7 h). We showed that the edema formation in the early phase was antagonized by dipyrone (80 mg/kg, ip) and indomethacin (1 mg/kg, ip) by 52 per cent and 52 per cent, respectively, and that the late phase was resistant to these drugs. These result suggest that in the early phase prostaglandins appear to be involved in the process. However, the activation of the kinin cascade leading to the release of other mediators may be involved in the increase of edema in the late phase. To test this hypothesis, we investigated whether the release of nitric oxide (NO) is involved in the mechanism of endotoxin-induced rat paw edema during the late phase, using Nw-nitro-L-arginine methyl ester (L-NAME) (50 mug, ipl) as inhibitor of NO synthase and L-arginine (1 mg, ipl) as substrate of NO synthase. The paw edema induced by Etx was inhibited by L-NAME by 56 per cent and increased by L-arginine by 81 per cent. Furthermore, L-arginine given in combination with L-NAME completely reversed the inhibitions of Etx-induced edema produced by L-NAME. These results support the hypothesis that in the late phase NO production is associated with the edema evoked by Etx.