Vasorelaxant activity of Euphorbia furcillata Kunth mainly by activation of NO/cGMP pathway and calcium channel blockade / Actividad vasorrelajante de Euphorbia furcillata Kunth principalmente por activación de la vía NO/GMPc y bloqueo de canales de calcio]

The aim of current study was to determinate ex vivo and chromatographic fingerprint by HPLC of four extracts of Euphorbia furcillata K. Ethyl acetate extract of Euphorbia furcillata (EaEEf) was the most effective and potent extract (Emax=98.69±1.24%) and its effect was partially endothelium-dependent. Functional vasorelaxant mechanism of action of EaEEf was determinate, EaEEf showed efficient relaxation of KCl [80 mM]-induced contraction and norepinephrine and CaCl2 contraction curves showed diminution of maximal contraction in the presence of EAEEf and EaEEf-relaxation curve was shifted to the right in the presence of L-NAME (nitric oxide synthase inhibitor) and ODQ (guanylate cyclase inhibitor). Chromatographic fingerprints analysis suggests presence of diterpenoid such as abietane, tigliane, and ingenane skeletons. Our experiments suggest the EaEEf vasorelaxant activity could be attributed to diterpenoid molecules whose mechanism involves nitric oxide production and calcium channel blockade.

Se determinó el efecto vasorrelajante ex vivo y los perfiles cromatográficos mediante HPLC de cuatro extractos de Euphorbia furcillata K.. El extracto de acetato de etilo de E. furcillata (EaEEf) fue el más eficaz y potente en la contracción inducida por norepinefrina (Emax=98.69±1.24%) y el efecto fue parcialmente dependiente del endotelio vascular. Se determinó el mecanismo de acción vasorrelajante para EaEEf, este mostró ser eficaz sobre la contracción inducida por KCl [80 mM] y la curva de contracción en respuesta a norepinefrina y CaCl2 en presencia de EaEEf mostró disminución en la contracción máxima, mientras que la curva de relajación de EaEEf en presencia de L-NAME (inhibidor de óxido nítrico sintasa) y ODQ (inhibidor de guanilato ciclasa) se desplazó hacia la derecha. El análisis cromatográfico de EaEEf sugiere la presencia de moléculas diterpenoides como abietano, tigliano y esqueletos de ingenano. Nuestros resultados sugieren que el efecto vasorrelajante de EaEEf podría atribuirse a moléculas diterpenoides, cuyo mecanismo de acción involucra la producción de óxido nítrico y bloqueo de canales de calcio.

Endocannabinoid system--a novel target for cardiometabolic risk.

The endocannabinoid system (EC) plays a significant role in appetite drive and associated behaviours. Therefore attenuation of the activity of the EC system would have therapeutic benefit in treating disorders that might have a component of excess appetite drive or over-activity of the endocannabinoid system, such as obesity, ethanol and other drug abuse, and a variety of central nervous system and other disorders. Antagonists of cannabinoid receptors have been designed through rational drug discovery essential to exploit these novel targets for potential in obesity, metabolism, addiction, pain and neurologic disorders. Rimonabant is the only compound in this group which along this pathway is now approved as a selective CB (1) (cannabinoid receptor subtype 1) antagonist, or inverse agonist, in the European Union and India and under regulatory review in the United States for the treatment of obesity and associated cardiometabolic risk.

Effect of amlodipine on insulin resistance & tumor necrosis factor-alpha levels in hypertensive obese type 2 diabetic patients.

BACKGROUND & OBJECTIVES: Tumour necrosis factor-alpha (TNF-alpha) has been suggested to play a key role in insulin resistance (IR) in obesity and may contribute to the development of type 2 diabetes mellitus. Recently, studies are focused on the effect of antihypertensive drugs on insulin sensitivity and cytokines. We undertook this study to evaluate the effect of amlodipine, a long-acting dihydropyridine calcium channel blocker treatment on TNF-alpha, homeostasis model assessment (HOMA) IR and leptin levels in obese hypertensive type 2 diabetic patients. METHODS: Amlodipine 5-10 mg for 12 wk was given to type 2 diabetic patients in the amlodipine group. Pre- and post-treatment values of laboratory parameters in the amlodipine group were compared with those of normotensive nondiabetic obese controls. At baseline blood pressures (BP) and metabolic parameters were measured in all patients and repeated after 12 wk in the amlodipine group. RESULTS: Basal waist-to-hip ratio, systolic and diastolic BPs, fasting glucose, TNF-alpha and HOMAIR values of the amlodipine group were higher than the control group. No difference was detected in body mass index, fasting insulin, hemoglobin A1c and leptin values between groups. The systolic and diastolic BPs, fasting glucose, HOMA-IR and TNF-alpha values decreased significantly after the treatment. But, there was no correlation between percentage change in TNF-alpha and HOMA-IR. INTERPRETATION & CONCLUSION: Besides reducing BP, amlodipine seemed to improve IR and decrease TNF-alpha levels. In this context, these properties may provide additional benefits of antihypertensive drug regimens chosen for this population, but larger group interventions are needed.

Análise dos padröes da dopplerfluxometria em gestantes hipertensas crônicas tratadas com verapamil sob forma oral contínua / Analysis of dopplerfluxometry standars in chronically hypertensive pregnant women treated with verapamil under continuous oral form

O artigo comunica estudo de corte, tipo caso/controle, prospectivo, duplo-cego, placebo controlado, que analisa a açåo de um bloqueador dos canais de cálcio (verapamil) em gestantes hipertensas crônicas de características leve e moderada. Através da dopplerfluxometria realizada antes e depois da introduçåo do hipotensor (intervalo de 30 dias), será avaliada umA possível modificaçåo nos fluxos útero e fetoplacentário. O trabalho baseia-se na hipótese de que o efeito anti-hipertensivo seria acompanhado de melhor fluxo uterino e fetal, melhorando assim o prognóstico materno e perinatal. Para justificar o estudo, apresenta referencial teórico sobre a utilizaçåo da dopplerfluxometria, do verapamil e porque a abordagem em gestantes hipertensas crônicas nåo graves

Influence of the sarcoplasmic reticulum on the inotropic responses of the rat myocardium resulting from changes in rate and rhythm

1. The role of the sarcoplasmic reticulum (SR) in the inotropic responses produced by changes in stimulation rate and rhythm and resting tension was investigated in the rat myocardium. 2. Rat papillary muscles contracting isometrically (basic stimulation rate = 30/min) were superfused in vitro with normal Krebs solution and after addition of ryanodine (1 microM). Post-rest potentiation was obtained after pauses of 5, 10, 15, 30, 60 and 120 s, and the stimulation rate was changed from 6 to 90 bpm. Post-extrasystolic potentiation was induced by interpolating an extra stimulus after an interval of 413 +/- 15 ms. NiCl2 (2 mM) was used to confirm that contractions obtained after SR blockade with ryanodine were activated only by sarcolemmal calcium influx. 3. In the presence of ryanodine, the post-rest potentiation phenomenon disappears and the force-frequency relationship changes from the typical force decrease produced by rate increase to force increase. Under the effect of ryanodine, resting tension increased with the increase in stimulation rate. This behavior was enhanced by reducing extracellular KCl from 5.4 mM to 1 mM. This maneuver decreases Na(+)-K(+)-ATPase and increases intracellular Na+ activity, which reduces Ca2+ extrusion through the Na(+)-Ca2+ exchange mechanism. 4. SR participation in the post-extrasystolic potentiation phenomenon is also suggested because ryanodine treatment reversed the extrasystolic force depression into potentiation. In the presence of ryanodine, blockade of Ca2+ influx with NiCl2 (2 mM) abolished isometric contractions indicating that after SR blockade contractions are mainly dependent on sarcolemmal Ca2+ influx. 5. The results suggest that the SR is involved in the genesis of post-rest potentiation and contributes to the typical force-frequency relationship of the rat myocardium and to the post-extrasystolic potentiation phenomenon. Moreover, SR activity seems to be important for the maintenance of low resting tension in the cardiac muscle, which may represent a safety factor against contractures during inotropic changes produced in rate and rhythm.

Utilizacao dos bloqueadores dos canais de calcio no controle das sindromes hipertensivas da gravidez / Calcium channel blocking agents in hypertension syndromes of pregnancy

Os bloqueadores de canais de calcio promovem um novo conceito para o tratamento das sindromes hipertensivas que acometem a gravidez. Investigacoes clinicas sugerem um importante papel deste grupo de substancias, representando uma excelente alternativa para os ambulatorios e enfermarias de alto risco obstetrico. Apesar dos diferentes tipos de bloqueadores disponiveis apresentaram mecanismo geral de acao parecidos, existem diferentes propriedades inerentes a cada um, permitindo assim utilizacao clinica diferenciada. Este artigo procurou admitir primeiramente uma abordagem geral sobre mecanismo de acao, vantagens e desvantagens de todos os bloqueadores dos canais de calcio, para em seguida particularizar a utilizacao do verapamil, justificando a escolha da Disciplina de Obstetricia da Universidade do Rio de Janeiro, que faz deste farmaco sua primeira linha de acao no controle da hipertensao na gravidez

Rol del calcio intracelular en la nefrotoxicidad por gentamicina / Role of increased intracellular calcium in the nephrotoxicity produced by gentamicin

Recientemente se ha llamado la atención sobre el rol que tendría el aumento del calcio intracelular en el mecanismo de la injuria celular isquémica y de otras formas de injurias. Para evaluar ésta hipótesis utilizamos el modelo de daño renal tubular tóxico producido por la gentamicina. Nosotros tratamos ratas con verapamil (V) (Bloqueante de los canales de calcio), antes y después de provocarle una nefrotoxicidad por gentamicina (G) y no encontramos protección de la nefrotoxicidad observándose una disminución similar del Clearance de Creatinina (G: 0,47 ñ 0,09; G + V: 0,59 ñ 0,05 ml/min/100 g peso corporal), un incremento semejante de la excreción fraccional de sodio (G: 1,68 ñ 0,50; G + V: 1,23 ñ 0,1%) y el mismo grado de daño tubular histológico (G: 3 ñ 0,23; G + V: 2,7 ñ 0,19). El aumento de la disponibilidad de calcio extracelular, producido por la hipercalcemia inducida por vitamina D, (H), durante la producción de toxicidad renal por gentamicina, no exacerbó la injuria tubular renal como lo demuestran la misma disminución de Clearance de creatinina (G: 0,18 ñ 0,2; G + H: 0,6 ñ 0,1 ml/min/100 g peso corporal), el mismo aumento de la excreción fraccional de sodio (G: 1,25 ñ 0,2; G + H: 1,5 ñ 0,3%) y el mismo grado de daño tubular histológico (G: 1,85 ñ 0,26; G + H: 2 ñ 0,37). Nuestros resultados no apoyan la hipótesis que propone el aumento de calcio intracelular como mediador de la injuria nefrotóxica