RESUMEN
Growing concerns on free radicals are the oxidative processes associated with physiological damage. The consumption of functional foods and use of plants with antioxidant capacity are widespread. Given the importance of determining antioxidant capacity in relation to the therapeutic effect, this study was aimed at evaluating cinnamon extract (Cinnamomum sp.) in commercial samples by spectrophotometric and voltammetric methods and assessing the vascular activity of some samples. The spectrophotometric methods performed were DPPH (1,1-diphenyl-2-picrihydrazine), ABTS (2,21-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)), and Folin-Ciocalteu radical sequestration assays. For the electrochemical experiments, a three-electrode system was used, consisting of carbon paste electrode, platinum wire, and Ag/AgCl/KClsat, representing the working, auxiliary, and reference electrodes, respectively. The electroanalytical methods used were differential pulse, square wave, and cyclic voltammetries. The extracts were prepared in hydroalcoholic solution. A calibration curve with gallic acid was calculated to quantify their equivalent amounts in the analyzed extract. The correlation between the electrochemical approach and the total phenols calculated by the ABTS, DPPH, and Folin-Ciocalteu methods was 0.63, 0.7, and 0.73, respectively, with 1 being an ideal directly proportional correlation. The correlation between spectrophotometric methods was 0.83. A biosensor was developed in a carbon paste electrode using the enzyme laccase, obtained by the fungus Marasmiellus colocasiae. It was observed that the antioxidant profile of the cinnamon samples had an analytical sign improvement of up to 4 times when compared with the electrode without the modification. The samples were analyzed by mass spectrometer, and the main chemical markers found were coumarin, cinnamaldehyde, and eugenol. Pharmacological trials showed that these samples also induce a significant vasorelaxant effect associated to antioxidant potential on vascular injury induced by oxidative stress. Thus, cinnamon showed a high antioxidant capacity, in agreement with the results obtained in other studies, emphasizing its importance as a functional food.
Asunto(s)
Antioxidantes , Cinnamomum zeylanicum , Antioxidantes/farmacología , Oxidación-Reducción , Fenoles , EspectrofotometríaRESUMEN
BACKGROUND: Acetaminophen (APAP) is the most widely used analgesic and antipyretic in the world. However, in high or continuous doses, it can cause serious side effects including blood pressure variability and cardiovascular injuries, which are barely explored. This study aimed to evaluate the acute effect of APAP treatment on vascular tone focused on the blocking of Ca2+ channels. METHODS: Rats were treated with APAP orally by gavage (500 mg/kg/single dose). After 12 h, the aorta was isolated for vascular reactivity studies in an isolated organ bath. Vascular contraction and relaxation were measured after different stimuli. Moreover, molecular docking studies were performed to evaluate the action of NAPQI (APAP metabolite) on L-type calcium channels. RESULTS: Phenylephrine-induced maximal vascular contraction was reduced in the APAP group (138.4 ± 9.2%) compared to the control group (172.2 ± 11.1%). APAP treatment significantly reduced contraction induced by Ca2+ influx stimulated with phenylephrine or KCl and reduced contraction mediated by Ca2+ released from the sarcoplasmic reticulum induced by caffeine. There was no difference in vascular relaxation induced by acetylcholine or sodium nitroprusside. Computational molecular docking demonstrated that NAPQI is capable of blocking L-type Ca2+ channels (Cav1.2), which would limit the influx of Ca2+. CONCLUSION: These results suggest that APAP treatment causes an anticontractile effect in rat aorta, possibly by blocking the influx of Ca2+ through L-type channels (Cav1.2).
Asunto(s)
Acetaminofén , Canales de Calcio Tipo L , Acetaminofén/metabolismo , Acetaminofén/farmacología , Animales , Aorta , Calcio/metabolismo , Canales de Calcio Tipo L/metabolismo , Simulación del Acoplamiento Molecular , Fenilefrina/farmacología , RatasRESUMEN
In this work we report the vasorelaxant activity of 7-ß-O-glycosides obtained with biosynthesis of naringenin-7-ß-O-glycoside (3) and quercetin-7-ß-O-glycoside (4). These compounds were obtained from naringenin (1) and quercetin (2) glycosylation catalyzed by Beauveria bassiana ATCC 7159. Screening of the best strain as a catalyst for glycosylation was carried out and the reaction conditions established. Cultures were grown in PDSM medium for 7 days at 27 °C. After purification by reverse-phase preparative HPLC, naringenin-7-ß-O-glycoside (3) and quercetin-7-ß-O-glycoside (4) were identified by (1)H and (13)C NMR. The right position and ß-configuration of the glucose was determined through HSQC and HMBC experiments. The vasorelaxation potential of naringenin, quercetin and its glycosylated derivatives was evaluated using isolated aorta in vitro models. Interestingly, results suggest that vasorelaxation properties of naringenin, rutin and its glycosides are due to different pathways.
Asunto(s)
Flavanonas/biosíntesis , Flavanonas/farmacología , Flavonoides/química , Glucósidos/biosíntesis , Glucósidos/farmacología , Quercetina/análogos & derivados , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacología , Animales , Aorta/efectos de los fármacos , Beauveria/metabolismo , Biocatálisis , Flavanonas/química , Flavanonas/metabolismo , Flavonoides/metabolismo , Glucósidos/química , Glicosilación , Técnicas In Vitro , Masculino , Estructura Molecular , Quercetina/biosíntesis , Quercetina/química , Quercetina/aislamiento & purificación , Quercetina/metabolismo , Quercetina/farmacología , Ratas Wistar , Vasodilatadores/aislamiento & purificaciónRESUMEN
Nitric oxide (NO) has been demonstrated to be the primary agent in relaxing airways in humans and animals. We investigated the mechanisms involved in the relaxation induced by NO-donors, ruthenium complex [Ru(terpy)(bdq)NO(+)](3+) (TERPY) and sodium nitroprusside (SNP) in isolated trachea of rats contracted with carbachol in an isolated organs chamber. For instance, we verified the contribution of K(+) channels, the importance of sGC/cGMP pathway, the influence of the extra and intracellular Ca(2+) sources and the contribution of the epithelium on the relaxing response. Additionally, we have used confocal microscopy in order to analyze the action of the NO-donors on cytosolic Ca(2+) concentration. The results demonstrated that both compounds led to the relaxation of trachea in a dependent-concentration way. However, the maximum effect (E(max)) of TERPY is higher than the SNP. The relaxation induced by SNP (but not TERPY) was significantly reduced by pretreatment with ODQ (sGC inhibitor). Only TERPY-induced relaxation was reduced by tetraethylammonium (K(+) channels blocker) and by pre-contraction with 75mM KCl (membrane depolarization). The response to both NO-donors was not altered by the presence of thapsigargin (sarcoplasmic reticulum Ca(2+)-ATPase inhibitor). The epithelium removal has reduced the relaxation only to SNP, and it has no effect on TERPY. The both NO-donors reduced the contraction evoked by Ca(2+) influx, while TERPY have shown a higher inhibitory effect on contraction. Moreover, the TERPY was more effective than SNP in reducing the cytosolic Ca(2+) concentration measured by confocal microscopy. In conclusion, these results show that TERPY induces airway smooth muscle relaxation by cGMP-independent mechanisms, it involves the fluxes of Ca(2+) and K(+) across the membrane, it is more effective in reducing cytosolic Ca(2+) concentration and inducing relaxation in the rat trachea than the standard drug, SNP.
Asunto(s)
Donantes de Óxido Nítrico/farmacología , Nitroprusiato/farmacología , Rutenio/química , Animales , Calcio/metabolismo , Citosol/efectos de los fármacos , Citosol/metabolismo , Técnicas In Vitro , Masculino , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Donantes de Óxido Nítrico/química , Nitroprusiato/química , Ratas , Ratas Wistar , Tráquea/efectos de los fármacos , Tráquea/fisiologíaRESUMEN
The perivascular nerve network expresses a Ca2+ receptor that is activated by high extracellular Ca2+ concentrations and causes vasorelaxation in resistance arteries. We have verified the influence of perivascular nerve fibers on the Ca2+-induced relaxation in aortic rings. To test our hypothesis, either pre-contracted aortas isolated from rats after sensory denervation with capsaicin or aortic rings acutely denervated with phenol were stimulated to relax with increasing extracellular Ca2+ concentration. We also studied the role of the endothelium on the Ca2+-induced relaxation, and we verified the participation of endothelial/nonendothelial nitric oxide and cyclooxygenase-arachidonic acid metabolites. Additionally, the role of the sarcoplasmic reticulum, K+ channels and L-type Ca2+ channels on the Ca2+-induced relaxation were evaluated. We have observed that the Ca2+-induced relaxation is completely nerve independent, and it is potentiated by endothelial nitric oxide (NO). In endothelium-denuded aortic rings, indomethacin and AH6809 (PGF2alpha receptor antagonist) enhance the relaxing response to Ca2+. This relaxation is inhibited by thapsigargin and verapamil, while was not altered by tetraethylammonium. In conclusion, we have shown that perivascular nervous fibers do not participate in the Ca2+-induced relaxation, which is potentiated by endothelial NO. In endothelium-denuded preparations, indomethacin and AH6809 enhance the relaxation induced by Ca2+. The relaxing response to Ca2+ was impaired by verapamil and thapsigargin, revealing the importance of L-type Ca2+ channels and sarcoplasmic reticulum in this response.
Asunto(s)
Aorta Torácica/fisiología , Canales de Calcio Tipo L/efectos de los fármacos , Calcio/fisiología , Retículo Sarcoplasmático/efectos de los fármacos , Vasodilatación/fisiología , Animales , Aorta Torácica/inervación , Ácido Araquidónico/metabolismo , Calcio/administración & dosificación , Endotelio Vascular/fisiología , Líquido Extracelular/metabolismo , Técnicas In Vitro , Masculino , Desnervación Muscular , Óxido Nítrico/fisiología , Prostaglandina-Endoperóxido Sintasas/metabolismo , Ratas , Ratas Wistar , Vasodilatación/efectos de los fármacosRESUMEN
AIMS: Following sinoaortic denervation (SAD), isolated rat aortas present oscillatory contractions and demonstrate a heightened contraction for alpha-adrenergic agonists. Our aim was to verify the effects of SAD on connexin43 (Cx43) expression and phenylephrine-induced contraction in isolated aortas. METHODS AND RESULTS: Three days after surgery (SAD or sham operation), isolated aortic rings were exposed to phenylephrine and acetylcholine (0.1-10 microM) in the presence or absence of the gap junction blocker 18beta-glycyrrhetinic acid (18beta-GA, 100 microM). Vascular reactivity to potassium chloride (KCl, 4.7-120 mM) was also examined. The incidence of rats presenting oscillatory contractions was measured. Effects of SAD on the vascular smooth muscle expression of the Cx43 mRNA by RT-PCR and western blotting for Cx43 protein were examined. Phenylephrine-induced contraction was higher in SAD rat aortas compared with the control. In the presence of 18beta-GA, the response to phenylephrine was similar in both groups. Oscillatory contractions were observed in 10/10 SAD rat aortas vs. 2/10 controls. Relaxing response to acetylcholine was similar in both groups, but in the presence of 18beta-GA, the response to acetylcholine decreased significantly in the sham-operated group (82.7 +/- 7.6% reduction of relaxation), whereas a half-maximal relaxation (reduction of 46.2 +/- 5.3%) took place in SAD rat aortas. KCl-induced contraction was similar in both groups. Following SAD, RT-PCR revealed significantly increased levels of Cx43 mRNA (9.85 fold, P < 0.01). Western blot analysis revealed greater levels of Cx43 protein (P < 0.05). CONCLUSION: Blood pressure variability evoked by SAD leads to increased expression of Cx43, which could contribute to enhanced phenylephrine-induced contraction and oscillatory activity in isolated aortas.
Asunto(s)
Aorta Torácica/metabolismo , Presión Sanguínea , Conexina 43/metabolismo , Uniones Comunicantes/metabolismo , Músculo Liso Vascular/metabolismo , Animales , Aorta Torácica/inervación , Comunicación Celular , Desnervación , Expresión Génica , Masculino , Ratas , Ratas Wistar , Regulación hacia ArribaRESUMEN
Sinoaortic denervation is characterized by arterial pressure lability, without sustained hypertension. Aortas isolated from rats with sinoaortic denervation present rhythmic contractions. We studied the participation of distinct Ca(2+) sources in the maintenance of the oscillations. Three days after the surgeries, aortic rings were placed in an organ chamber, and the incidence of aortas presenting rhythmic contractions was measured. Specific drugs were employed to analyse the participation of the Ca(2+) released from the sarcoplasmic reticulum [2-APB (diphenylborinic acid 2-aminoethyl ester), thapsigargin and ryanodine] and external Ca(2+) entry [Bay K 8644, verapamil and DMB (dimethylbenzyl amiloride)] on the rhythmic contractions. Additionally, we verified the effects of chloride channel blocker NPPB [5-nitro-2-(3-phenylpropylamino)-benzoic acid] on the maintenance of the rhythmic contractions. Under phenylephrine stimulus, sinoaortic-denervated rat aortas exhibited rhythmic contractions in the frequency of 4.5 +/- 0.50 cycles/min. and an amplitude of 0.465 +/- 0.05 g. 2-APB, thapsigargin and ryanodine inhibited the rhythmic contractions. Bay K 8644 increased the oscillations, reaching maximum values with a concentration of 50 nM (18.5 +/- 2.5 cycles/min.). The rhythmic contractions were inhibiting by verapamil and Ca(2+)-free solution. DMB and NPPB did not alter the oscillations. In conclusion, we observed that aorta isolated from sinoaortic-denervated rats present rhythmic contractions. Moreover, drugs that impaired intracellular Ca(2+) release from sarcoplasmic reticulum interrupted the oscillations. The oscillations also depend on the extracellular Ca(2+) entry through L-type Ca(2+).
Asunto(s)
Aorta Torácica/efectos de los fármacos , Desnervación Autonómica , Señalización del Calcio/efectos de los fármacos , Moduladores del Transporte de Membrana/farmacología , Vasoconstricción/efectos de los fármacos , Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico/farmacología , Amilorida/análogos & derivados , Amilorida/farmacología , Animales , Aorta Torácica/inervación , Aorta Torácica/metabolismo , Presión Sanguínea/efectos de los fármacos , Compuestos de Boro/farmacología , Agonistas de los Canales de Calcio/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo L/efectos de los fármacos , Canales de Calcio Tipo L/metabolismo , Canales de Cloruro/efectos de los fármacos , Canales de Cloruro/metabolismo , Relación Dosis-Respuesta a Droga , Receptores de Inositol 1,4,5-Trifosfato/efectos de los fármacos , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Nitrobenzoatos/farmacología , Periodicidad , Fenilefrina/farmacología , Ratas , Ratas Wistar , Rianodina/farmacología , Canal Liberador de Calcio Receptor de Rianodina/efectos de los fármacos , Canal Liberador de Calcio Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/efectos de los fármacos , Retículo Sarcoplasmático/metabolismo , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/antagonistas & inhibidores , ATPasas Transportadoras de Calcio del Retículo Sarcoplásmico/metabolismo , Bloqueadores de los Canales de Sodio/farmacología , Intercambiador de Sodio-Calcio/efectos de los fármacos , Intercambiador de Sodio-Calcio/metabolismo , Tapsigargina/farmacología , Factores de Tiempo , Vasoconstrictores/farmacología , Verapamilo/farmacologíaRESUMEN
Sinoaortic deafferentation (SAD) is characterized by arterial pressure lability, without sustained hypertension. Although SAD rats did not become hypertensive, their isolated aortas exhibit RCs. We have investigated whether these RCs are influenced by endothelium. Aortic rings were placed in an organ chamber, and the frequency and amplitude of the RCs were measured in SAD rat aortas with intact and denuded endothelium. Moreover, the participation of endothelial NO and cGMP pathways on the RCs were analyzed through the use of such drugs as L-NAME, acetylcholine, ODQ, L-arginine, and oxyhemoglobin. Indomethacin was used to evaluate the influence of prostanoids on the RCs. Under phenylephrine stimulus, 100% of SAD rat aortas presented RCs, with higher frequency and amplitude in denuded endothelium (8.5 +/- 0.50 cycles/2 min and 0.465 +/- 0.05 g, respectively) compared with intact endothelium (4.5 +/- 0.50 cycles/2 min and 0.311 +/- 0.04 g, respectively). In intact-endothelium aortas, L-NAME, ODQ, and oxyhemoglobin raised the frequency and amplitude of the RCs to values similar to those found in denuded endothelium. L-arginine and indomethacin did not alter the RCs. In conclusion, SAD rat aortas present rhythmic contractions, which are negatively modulated by endothelial NO. Our results indicate that endothelium-derived NO (and not prostanoids), acting through the cGMP pathway, has an inhibitory effect on the oscillations.
Asunto(s)
Aorta Torácica/fisiología , Endotelio Vascular/fisiología , Contracción Muscular/fisiología , Músculo Liso Vascular/fisiología , Óxido Nítrico/fisiología , Acetilcolina/farmacología , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/inervación , Arginina/farmacología , Desnervación Autonómica , Presión Sanguínea/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Endotelio Vascular/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Guanilato Ciclasa/antagonistas & inhibidores , Frecuencia Cardíaca/efectos de los fármacos , Indometacina/farmacología , Masculino , Contracción Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , NG-Nitroarginina Metil Éster/farmacología , Nitroprusiato/farmacología , Oxadiazoles/farmacología , Oxihemoglobinas/farmacología , Fenilefrina/farmacología , Quinoxalinas/farmacología , RatasRESUMEN
1. The spontaneous variation of blood pressure is defined as arterial pressure lability. Sinoaortic denervation (SAD) is characterized by arterial pressure lability without sustained hypertension. 2. The phenomenon of spontaneous oscillatory contractions (SOCs) occurs more frequently in the vascular beds of hypertensive animals. In large arteries, such as the aorta, SOCs occur only occasionally or they can be initiated by application of chemical stimuli. 3. In the present study, we investigated whether the arterial pressure lability evoked by SAD could be related to the emergence of SOCs in the aorta of rats submitted to SAD compared with sham-operated rats (SO). Three days after surgery (SAD or SO), aortic rings were placed in an organ chamber and the incidence (percentage of rats presenting SOCs), frequency (number of SOCs in 10 min) and amplitude (mN) of SOCs were measured. The participation of external Ca(2+) and K(+) channels in the maintenance of SOCs was also verified. 4. The incidence and frequency of SOCs were higher in endothelium-denuded aortas from SAD rats (82% and 38 +/- 4 SOCs/10 min, respectively) than in aortas from SO rats (40% and 14 +/- 2 SOCs/10 min, respectively). In aortas from SAD rats, verapamil (0.2 micromol/L), pinacidil (0.3 micromol/L) and tetraethylammonium (TEA; 5 mmol/L) totally inhibited SOCs, whereas increasing the CaCl(2) concentration to 2.0 and 2.5 mmol/L increased the frequency of SOCs. Interestingly, increasing the concentration of CaCl(2) to 3.5 mmol/L inhibited these contractions in aortas from SAD rats. 5. These results show that although SAD rats did not become hypertensive, their aortas were capable of initiating SOCs without the application of any chemical stimuli. The SOCs seem to be dependent on Ca(2+) influx sensitive to verapamil and also involve K(+) channels sensitive to pinacidil and TEA.
Asunto(s)
Aorta Torácica/metabolismo , Desnervación Autonómica , Presión Sanguínea , Canales de Calcio/metabolismo , Calcio/metabolismo , Canales de Potasio/metabolismo , Potasio/metabolismo , Vasoconstricción , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/inervación , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio/efectos de los fármacos , Cloruro de Calcio/farmacología , Masculino , Oscilometría , Pinacidilo/farmacología , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio/efectos de los fármacos , Ratas , Ratas Wistar , Tetraetilamonio/farmacología , Factores de Tiempo , Vasoconstricción/efectos de los fármacos , Vasodilatadores/farmacología , Verapamilo/farmacologíaRESUMEN
Experiments were carried out to investigate the heart rate of Synbranchus marmoratus after changing the temperature of the water contained in the experimental chamber of the acclimated fish (from 25 to 35 degrees C and from 25 to 15 degrees C). Then, an isometric cardiac muscle preparation was used to test the relative importance of Ca(2+) released from the sarcoplasmic reticulum and Ca(2+) influx across the sarcolemma for the cardiac performance under different thermal conditions: 25 degrees C (acclimation temperature), 15 and 35 degrees C. Adrenaline and ryanodine were used to modulate the Ca(2+) flux through the sarcolemma and the sarcoplasmic reticulum, respectively. Ryanodine reduced the peak tension by approximately 47% at 25 degrees C, and by 53% at 35 degrees C; however, it had no effect at 15 degrees C. A high adrenaline concentration was able to ameliorate the negative effects of ryanodine. Despite increasing the peak tension, adrenaline increased the times necessary for contraction and relaxation. We conclude that the sarcoplasmic reticulum is active in contributing Ca(2+) to the development of tension at physiological contraction frequencies. The adrenaline-stimulated Ca(2+) influx is able to increase the peak tension, even after addition of ryanodine, at physiologically relevant temperatures and pacing frequencies.