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Benzodiazepines and "Z-drugs" (BZD/Z) are overprescribed in many countries. This study evaluates their consumption in a social security sector health insurance provider with national coverage in Argentina. With a descriptive and observational approach, outpatient dispensations of BZD/Zs were analyzed for people over 18 years old from April 2020 to March 2021, disaggregated by sex, age, active ingredient, and half-life. An annual prevalence of use of 11.6% was found among the 431,445 adult affiliates, with higher rates in women and in those over age 60. Overall consumption of BZD/Zs was 77.6 defined daily doses (DDD) per 1000 enrollee-days. The average user received 5.1 annual dispensations and the equivalent of 1.4 DDD for each day of the year. BZD/Zs with long half-life were the most used. We found high levels of BZD/Z consumption and for longer periods than recommended. It is necessary to improve the quality of consumption and reduce the negative impact of inappropriate use of these drugs among treated individuals.
Las benzodiazepinas y los "fármacos Z" (BZD-Z) se prescriben en exceso en muchos países. Este estudio evaluó su consumo en una organización de la seguridad social (obra social) de Argentina de alcance nacional. A partir de un diseño observacional descriptivo se analizó la dispensa ambulatoria de BZD-Z, entre abril 2020 y marzo 2021, a mayores de 18 años; desagregada por sexo, edad, principio activo y vida media. Se encontró una prevalencia anual de uso del 11,6% entre los 431.445 afiliados adultos, con valores más elevados en las mujeres y mayores de 60 años. El consumo global de BZD-Z fue de 77,6 dosis diarias definidas (DDD) cada 1.000 afiliados-día. El usuario promedio recibió 5,1 dispensas anuales y el equivalente a 1,4 DDD por cada día del año. Las BZD-Z más usadas fueron las de vida media larga. El consumo de BZD-Z resultó elevado y más prolongado que lo recomendado. Es necesario mejorar la calidad en el consumo y reducir el impacto negativo del uso inapropiado de estos fármacos entre los individuos tratados.
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Benzodiazepinas , Preparaciones Farmacéuticas , Adolescente , Adulto , Argentina , Benzodiazepinas/efectos adversos , Femenino , Humanos , Renta , Persona de Mediana Edad , Seguridad SocialRESUMEN
ß-Adrenergic blockers are no longer recommended as first-line therapy due to the reduced cardioprotection of traditional ß-blockers compared with other antihypertensive drugs. It is unknown whether third-generation ß-blockers share the limitations of traditional ß-blockers. The aim of the present study was to compare the effects of nebivolol or atenolol on central and peripheral systolic blood pressure (SBP) and its variability and target organ damage (TOD) in N-nitro-L-arginine methyl ester (L-NAME) hypertensive rats. Male Wistar rats were treated with L-NAME for 8 weeks together with oral administration of nebivolol 30 mg/kg (n = 8), atenolol 90 mg/kg (n = 8), or vehicle (n = 8). The control group was composed of vehicle-treated Wistar rats. SBP and its variability, as well as echocardiographic parameters, were assessed during the last 2 weeks of treatment. Tissue levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and transforming growth factor ß (TGF-ß), and histopathological parameters were evaluated in the left ventricle and aorta. Nebivolol had a greater ability than atenolol to decrease central SBP and mid-term and short-term blood pressure variability (BPV) in L-NAME rats. Echocardiographic analysis showed that nebivolol was more effective than atenolol on E/A wave ratio normalization. Compared with atenolol treatment, nebivolol had a greater protective effect on different TOD markers, inducing a decrease in collagen deposition and a reduction in the proinflammatory cytokines IL-6 and TNF-α in the left ventricle and aorta. Our findings suggest that the adverse hemodynamic profile and the reduced cardiovascular protection reported with traditional ß-blockers must not be carried forward to third-generation ß-blockers.
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Atenolol , Hipertensión , Nebivolol , Animales , Antihipertensivos/farmacología , Atenolol/farmacología , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Hipertensión/tratamiento farmacológico , Masculino , Nebivolol/farmacología , Ratas , Ratas Wistar , Resultado del TratamientoRESUMEN
Adenosine is involved in classic preconditioning in most species and acts especially through adenosine A1 and A3 receptors. The aim of the present study was to evaluate whether remote ischemic preconditioning (rIPC) activates adenosine A1 receptors and improves mitochondrial function, thereby reducing myocardial infarct size. Isolated rat hearts were subjected to 30 min of global ischemia and 60 min of reperfusion [ischemia-reperfusion (I/R)]. In a second group, before isolation of the heart, a rIPC protocol (3 cycles of hindlimb I/R) was performed. Infarct size was measured with tetrazolium staining, and Akt/endothelial nitric oxide (NO) synthase (eNOS) expression/phosphorylation and mitochondrial function were evaluated after ischemia at 10 and 60 min of reperfusion. As expected, rIPC significantly decreased infarct size. This beneficial effect was abolished only when 8-cyclopentyl-1,3-dipropylxanthine (adenosine A1 receptor blocker) and NG-nitro-l-arginine methyl ester (NO synthesis inhibitor) were administered during the reperfusion phase. At the early reperfusion phase, rIPC induced significant Akt and eNOS phosphorylation, which was abolished by the perfusion with an adenosine A1 receptor blocker. I/R led to impaired mitochondrial function, which was attenuated by rIPC and mediated by adenosine A1 receptors. In conclusion, we demonstrated that rIPC limits myocardial infarct by activation of adenosine A1 receptors at early reperfusion in the isolated rat heart. Interestingly, rIPC appears to reduce myocardial infarct size by the Akt/eNOS pathway and improves mitochondrial function during myocardial reperfusion. NEW & NOTEWORTHY Adenosine is involved in classic preconditioning and acts especially through adenosine A1 and A3 receptors. However, its role in the mechanism of remote ischemic preconditioning is controversial. In this study, we demonstrated that remote ischemic preconditioning activates adenosine A1 receptors during early reperfusion, inducing Akt/endothelial nitric oxide synthase phosphorylation and improving mitochondrial function, thereby reducing myocardial infarct size.
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Precondicionamiento Isquémico Miocárdico , Mitocondrias Cardíacas , Receptor de Adenosina A1 , Antagonistas del Receptor de Adenosina A1/uso terapéutico , Adenosina Trifosfato/biosíntesis , Animales , Inhibidores Enzimáticos/uso terapéutico , Masculino , Potencial de la Membrana Mitocondrial , Infarto del Miocardio/diagnóstico por imagen , Infarto del Miocardio/fisiopatología , Daño por Reperfusión Miocárdica/diagnóstico por imagen , Daño por Reperfusión Miocárdica/fisiopatología , Óxido Nítrico Sintasa de Tipo III/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo III/metabolismo , Nitroarginina/uso terapéutico , Consumo de Oxígeno , Ratas , Ratas Sprague-Dawley , Xantinas/uso terapéuticoRESUMEN
INTRODUCTION: Although main antihypertensive drugs are able to efficiently reduce blood pressure, only a third of treated hypertensive patients achieve optimal blood pressure control. Extensive interpatient variability on drug metabolism and oral disposition of blood pressure lowering drugs can contribute to this failure in hypertension management. Areas covered: The aim of the present review is to update the knowledge on the features of hepatic metabolism of the main antihypertensive agents, including ß-blockers, calcium channel blockers, angiotensin receptor blockers, and angiotensin converting enzyme inhibitors. The factors that contribute to the large interindividual variability of main antihypertensive drugs are also covered. Expert opinion: The variability of plasma concentration of antihypertensive drugs due to the involvement of hepatic metabolism can contribute to the inadequate control of blood pressure in the daily clinical practice. Genotype screening of specific hepatic drug-metabolizing enzymes may contribute to optimize dose selection and to increase the rate of blood pressure control in patients treated with specific ß-blockers, calcium channel blockers, and angiotensin receptor blockers.
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Antihipertensivos/administración & dosificación , Presión Sanguínea/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Antagonistas Adrenérgicos beta/administración & dosificación , Antagonistas Adrenérgicos beta/farmacocinética , Antagonistas de Receptores de Angiotensina/administración & dosificación , Antagonistas de Receptores de Angiotensina/farmacocinética , Antihipertensivos/farmacocinética , Antihipertensivos/farmacología , Bloqueadores de los Canales de Calcio/administración & dosificación , Bloqueadores de los Canales de Calcio/farmacocinética , Relación Dosis-Respuesta a Droga , Genotipo , HumanosRESUMEN
Methyl gallate is a gallotannin widely distributed in nature. Previous studies have demonstrated its antioxidant, anti-inflammatory, antimicrobial and anti-tumor activities. In the present study, the activity of methyl gallate on experimental models of inflammatory bowel disease has been investigated. Experimental colitis was induced in Sprague-Dawley rats through the intracolonic instillation of an acetic acid solution (2 mL, 4% v/v). Methyl gallate (100 and 300 mg/kg, p.o.) and the reference drug mesalazine (100 mg/kg, p.o.) were tested. Methyl gallate induced a significant reduction in the colon weight/length ratio and macroscopic lesion score. Besides, the malondialdehyde content and the GSSG/GSH ratio were remarkably decreased. Furthermore, the administration of methyl gallate reduced the expression of COX2, IL-6, TNFα and the severity of microscopic tissue damage induced by acetic acid, while the mean goblet cell density was significantly higher in both the group treated with methyl gallate and the one treated with mesalazine, in comparison with untreated animals. The Na+K+ATPase pump activity was recovered in treated groups (control: 827.2 ± 59.6, colitis: 311.6 ± 54.8, methyl gallate 100 mg/kg: 642.2 ± 175.0, methyl gallate 300 mg/kg: 809.7 ± 100.6, mesalazine: 525.3 ± 81.7). Methyl gallate was also found to induce a significant reduction in the castor oil-induced intestinal motility in Swiss mice, decreasing the peristalsis by 74.5 and 58.82% at 100 and 300 mg/kg p.o., respectively. This compound also antagonized the jejunum contractions induced by Ach and CaCl2. This study demonstrates that methyl gallate exerts beneficial effects in a preclinical model of intestinal disorders.
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Colitis/inducido químicamente , Colitis/tratamiento farmacológico , Ácido Gálico/análogos & derivados , Extractos Vegetales/uso terapéutico , Ácido Acético/toxicidad , Animales , Colitis/patología , Relación Dosis-Respuesta a Droga , Femenino , Ácido Gálico/farmacología , Ácido Gálico/uso terapéutico , Motilidad Gastrointestinal/efectos de los fármacos , Motilidad Gastrointestinal/fisiología , Ratones , Extractos Vegetales/farmacología , Ratas , Ratas Sprague-Dawley , Resultado del TratamientoRESUMEN
OBJECTIVE: This review covers the pharmacokinetics and pharmacodynamic of ß-blockers, the rationale for their use, some recent controversies in its use for managing hypertension, as well as, the beneficial properties of the third-generation ß-blockers beyond hypertension. BACKGROUND: The efficacy and safety of ß-blockers in the treatment of hypertension and other cardiovascular diseases have been established during more than 50 years of clinical experience. Recent updates of clinical guidelines have downgraded the use of ß-blockers for the treatment of uncomplicated hypertension to second and third line therapy. It is a well-known fact that ß-blockers exhibit heterogeneous pharmacokinetic and pharmacodynamic properties that clearly influence their clinical efficacy and tolerability in the management of essential hypertension. Conventional nonvasodilating ß-blockers (atenolol and metoprolol) are inferior to first-line antihypertensive agents in terms of cardioprotection due to lower ability to reduce central blood pressure and its variability and the adverse effects on glycemic and lipid metabolism. CONCLUSION: New vasodilating ß-blockers, mainly carvedilol and nebivolol, show enhanced hemodynamic and metabolic properties, which probably result in a higher prevention of major cardiovascular events in hypertensive patients. Despite head-to-head clinical trials comparing the effects of vasodilating vs nonvasodilating ß-blockers on hard clinical endpoints are lacking, the current evidence suggests that third-generation ß-blockers are superior to conventional ß-blockers for the prevention of cardiovascular events in patients with essential hypertension. Moreover, beyond their antihypertensive properties, third-generation ß-blockers also have pleiotropic, antioxidant and antiinflammatory effects that warrant a "promissory new era" of this newly group.
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Antagonistas Adrenérgicos beta/uso terapéutico , Antihipertensivos/uso terapéutico , Hipertensión Esencial/tratamiento farmacológico , Antagonistas Adrenérgicos beta/efectos adversos , Antihipertensivos/efectos adversos , Presión Sanguínea/efectos de los fármacos , Índice Glucémico/efectos de los fármacos , Humanos , Metabolismo de los Lípidos/efectos de los fármacosRESUMEN
The aim of this study was to demonstrate the effects of atrial natriuretic peptide (ANP) on organic cation transporters (OCTs) expression and activity, and its consequences on dopamine urinary levels, Na+, K+-ATPase activity and renal function. Male Sprague Dawley rats were infused with isotonic saline solution during 120 minutes and randomized in nine different groups: control, pargyline plus tolcapone (P+T), ANP, dopamine (DA), D-22, DA+D-22, ANP+D-22, ANP+DA and ANP+DA+D-22. Renal functional parameters were determined and urinary dopamine concentration was quantified by HPLC. Expression of OCTs and D1-receptor in membrane preparations from renal cortex tissues were determined by western blot and Na+, K+-ATPase activity was determined using in vitro enzyme assay. 3H-DA renal uptake was determined in vitro. Compared to P+T group, ANP and dopamine infusion increased diuresis, urinary sodium and dopamine excretion significantly. These effects were more pronounced in ANP+DA group and reversed by OCTs blockade by D-22, demonstrating that OCTs are implied in ANP stimulated-DA uptake and transport in renal tissues. The activity of Na+, K+-ATPase exhibited a similar fashion when it was measured in the same experimental groups. Although OCTs and D1-receptor protein expression were not modified by ANP, OCTs-dependent-dopamine tubular uptake was increased by ANP through activation of NPR-A receptor and protein kinase G as signaling pathway. This effect was reflected by an increase in urinary dopamine excretion, natriuresis, diuresis and decreased Na+, K+-ATPase activity. OCTs represent a novel target that links the activity of ANP and dopamine together in a common mechanism to enhance their natriuretic and diuretic effects.
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Factor Natriurético Atrial/metabolismo , Proteínas de Transporte de Catión/metabolismo , Dopamina/metabolismo , Sodio/metabolismo , Animales , Transporte Biológico , Membrana Celular/metabolismo , Cromatografía Líquida de Alta Presión , Diuresis/efectos de los fármacos , Dopamina/orina , Riñón/metabolismo , Túbulos Renales/metabolismo , Masculino , Natriuresis/efectos de los fármacos , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , ATPasa Intercambiadora de Sodio-Potasio/metabolismoRESUMEN
es
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NEW FINDINGS: What is the central question of this study? Ischaemia-reperfusion of peripheral tissues protects the heart from subsequent myocardial ischaemia-reperfusion injury, a phenomenon referred to as remote ischaemic preconditioning (rIPC). This study evaluated the possible myocardial triggers of rIPC. What is the main finding and its importance? Remote ischaemic preconditioning reduces infarct size through a vagal pathway and a mechanism involving phosphorylation of Akt and endothelial nitric oxide synthase, opening of mitochondrial ATP-dependent K(+) channels and an increase in mitochondrial H2 O2 production. All these phenomena occur before the myocardial ischaemia; hence, they could act as 'triggers' of rIPC. It has been proposed that remote ischaemic preconditioning (rIPC) activates a parasympathetic neural pathway. However, the myocardial intracellular mechanism of rIPC remains unclear. Here, we characterized some of the intracellular signals participating as rIPC triggers. Isolated rat hearts were subjected to 30 min of global ischaemia and 120 min of reperfusion (Non-rIPC group). In a second group, before the isolation of the heart, an rIPC protocol (three cycles of hindlimb ischaemia-reperfusion) was performed. The infarct size was measured with tetrazolium staining. Expression/phosphorylation of Akt and endothelial nitric oxide synthase (eNOS) and mitochondrial H2 O2 production were evaluated at the end of the rIPC protocol, before myocardial ischaemia-reperfusion. The rIPC significantly decreased the infarct size and induced Akt and eNOS phosphorylation. The protective effect on infarct size was abolished by cervical vagal section, l-NAME (an NO synthesis inhibitor) and 5-hydroxydecanoate (a mitochondrial ATP-dependent K(+) channel blocker). Mitochondrial production of H2 O2 was increased by rIPC, whereas it was abolished by cervical vagal section, l-NAME and 5-hydroxydecanoate. We conclude that rIPC activates a parasympathetic vagal pathway and a mechanism involving the phosphorylation of Akt and eNOS, the opening of mitochondrial ATP-dependent K(+) channels and the release of H2 O2 by the mitochondria. All these phenomena occur before myocardial ischaemia and could act as triggers of rIPC.
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Infarto del Miocardio/metabolismo , Isquemia Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , Miocardio/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Ácidos Decanoicos/farmacología , Corazón/efectos de los fármacos , Corazón/fisiopatología , Miembro Posterior/efectos de los fármacos , Miembro Posterior/metabolismo , Peróxido de Hidrógeno/metabolismo , Hidroxiácidos/farmacología , Precondicionamiento Isquémico Miocárdico/métodos , Masculino , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Reperfusión Miocárdica/métodos , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa de Tipo III/metabolismo , Sistema Nervioso Parasimpático/efectos de los fármacos , Sistema Nervioso Parasimpático/metabolismo , Fosforilación/efectos de los fármacos , Fosforilación/fisiología , Canales de Potasio/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Ratas Wistar , Nervio Vago/efectos de los fármacos , Nervio Vago/metabolismoRESUMEN
Con el objetivo en este estudio de evaluar los efectos cardiovasculares y la farmacocinética del nebivolol en ratas hipertensas por sobrecarga de fructosa y en ratas control, se registraron los efectos de la administración intravenosa de nebivolol, 3 mg/kg o 10 mg/kg, sobre la presión arterial, la frecuencia cardíaca y la variabilidad de la presión arterial a corto plazo y latido-a-latido, y se evaluó la farmacocinética enantioselectiva a partir del análisis de la concentración plasmática de los enantiómeros d-nebivolol y l-nebivolol. La variabilidad de la presión arterial a corto plazo y latido-a-latido se evaluó mediante la desviación estándar y el análisis espectral del registro de la presión arterial, respectivamente. El estado hipertensivo alteró la farmacocinética del nebivolol, evidenciado por una reducción en el aclaramiento del nebivolol en el grupo fructosa respecto del grupo control luego de la administración de la dosis más alta. El efecto antihipertensivo del nebivolol fue similar en ambos grupos, en tanto que el efecto bradicardizante fue mayor en las ratas del grupo control. Aunque no se observaron diferencias significativas en la variabilidad de la presión arterial latido-a-latido, la reducción de la variabilidad de la presión arterial a corto plazo inducida por el nebivolol fue significativamente superior en las ratas del grupo fructosa en comparación con los animales normotensos (-57,9% ± 11,8% vs. -19,6% ± 9,2%; p < 0,05). En conclusión, si bien el nebivolol reduce la presión arterial y la variabilidad de la presión arterial en ambos grupos, no se encontraron diferencias significativas en las ratas con sobrecarga de fructosa en cuanto a la farmacocinética y los efectos cardiovasculares, a excepción de una eficacia bradicardizante menor y una reducción mayor de la variabilidad de la presión arterial a corto plazo.
The cardiovascular and pharmacokinetic effects of nebivolol were evaluated in hypertensive fructose-fed and control rats, analyzing the effect of intravenously administered nebivolol 3 or 10 mg/kg on blood pressure, heart rate, and short-term and beat-to-beat blood pressure variability. The enantioselective pharmacokinetic profile of d- and l-nebivolol enantiomers was evaluated. Short-term and beat-to-beat blood pressure variability was assessed using standard deviation and blood pressure spectral analysis, respectively. The hypertensive state altered the pharmacokinetics of nebivolol, evidenced by reduction of nebivolol clearance in the fructose group compared to the control group after administration of the highest dose. The antihypertensive effect of nebivolol was similar in both groups, while the bradycardic effect was greater in control rats. Although no significant differences were found in beat-to-beat blood pressure variability, short-term blood pressure variability showed greater reduction after nebivolol administration in fructose-fed rats compared to control normotensive animals (-57.9%±11.8% vs.-19.6%±9.2%; p<0.05). In conclusion, although nebivolol reduces blood pressure and blood pressure variability in both groups, no significant differences were found in the pharmacokinetics and cardiovascular effects of fructose-fed rats, except for lower bradycardic efficacy and greater reduction in short-term blood pressure variability.
RESUMEN
In a previous research, we described that vagal stimulation increases the infarct size by sympathetic co-activation. The aim of this study was to determine if hemodynamic changes secondary to the vagal stimulation are able to activate sympathetic compensatory neural reflexes, responsible for increasing the infarct size. A second goal was to determine if intermittent vagal stimulation avoids sympathetic activation and reduces infarct size by muscarinic activation of the Akt/glycogen synthase kinase 3 ß (GSK-3ß) pathway. Rabbits were subjected to 30 min of regional myocardial ischemia and 3 h of reperfusion without vagal stimulation, or the following protocols of right vagus nerve stimulation for 10 min before ischemia: (a) continuous vagal stimulation and (b) intermittent vagal stimulation (cycles of 10 s ON/50 s OFF). Continuous vagal stimulation increased the infarct size (70.7 ± 4.3 %), even after right vagal section (68.6 ± 4.1 %) compared with control group (52.0 ± 3.7 %, p < 0.05). Bilateral vagotomy, pacing, and esmolol abolished the deleterious effect, reaching an infarct size of 43.3 ± 5.1, 43.5 ± 2.1, and 46.0 ± 4.6 % (p < 0.05), respectively. Intermittent stimulation reduced the infarct size to 29.8 ± 3.0 % (p < 0.05 vs I/R). This effect was blocked with atropine (50.2 ± 3.6 %, p < 0.05). Continuous vagal stimulation induced bradycardia and increased the loading conditions and wall stretching of the atria. These changes provoked the co-activation reflex of the sympathetic nervous system, observed by the rise in plasmatic catecholamine levels, which increased the infarct size. Sympathetic co-activation was abolished by continuous vagal stimulation with constant heart rate or parasympathetic deafferentation. Intermittent vagal stimulation attenuated the sympathetic tone and reduced the infarct size by the muscarinic activation of the Akt pathway and GSK-3ß inhibition. Continuous stimulation only phosphorylated Akt and GSK-3ß when esmolol was administered.
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Infarto del Miocardio/fisiopatología , Daño por Reperfusión Miocárdica/fisiopatología , Sistema Nervioso Simpático/fisiología , Nervio Vago/fisiología , Antagonistas de Receptores Adrenérgicos beta 1/farmacología , Animales , Antiarrítmicos/farmacología , Atropina/farmacología , Catecolaminas/sangre , Glucógeno Sintasa Quinasa 3/metabolismo , Glucógeno Sintasa Quinasa 3 beta , Hemodinámica , Masculino , Infarto del Miocardio/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , Propanolaminas/farmacología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Conejos , Reflejo , Transducción de Señal , Sistema Nervioso Simpático/efectos de los fármacos , Nervio Vago/efectos de los fármacosRESUMEN
The cardiovascular effects and pharmacokinetics of nebivolol were assessed in N(G)-nitro-l-arginine methyl ester (L-NAME) hypertensive and normotensive control rats. Male Wistar rats were randomly divided to drink tap water (control) or L-NAME solution for 2 weeks. The effects of nebivolol (3 or 10 mg kg(-1) i.v.) on blood pressure (BP), heart rate and BP variability (BPV) were recorded in awake L-NAME and control rats. Short-term and beat-to-beat BPV was assessed by the s.d. and spectral analysis of the BP recordings. Nebivolol pharmacokinetics was studied by means of traditional blood sampling. Nebivolol showed enantioselective pharmacokinetics in both experimental groups; the clearance and the volume of distribution of l-nebivolol were significantly greater than those of the d-enantiomer. The hypotensive response to nebivolol was significantly enhanced in L-NAME rats (Δmean arterial pressure (MAP): -16.1±1.1%, P<0.05 vs. control rats) compared with normotensive animals (ΔMAP: -1.4±2.1%). An analysis of the beat-to-beat BPV showed a greater reduction in VLF BPV in the L-NAME compare with the control rats. Nebivolol significantly reduced the low-frequency/high-frequency ratio in hypertensive L-NAME animals compared with normotensive rats. Short-term BPV was markedly reduced by nebivolol in both experimental groups, although the attenuation of the s.d. of BP recording was greater in L-NAME rats. In conclusion, the hypotensive efficacy of nebivolol is significantly enhanced in L-NAME rats compared with normotensive animals, which is most likely due to a greater reduction in vascular sympathetic activity. Nebivolol markedly attenuated short-term BPV in both experimental groups, suggesting that ß-blockers with additional pharmacological actions provide beneficial cardiovascular effects by controlling high BP and its short-term variability.
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Antagonistas Adrenérgicos beta/farmacología , Antagonistas Adrenérgicos beta/farmacocinética , Benzopiranos/farmacología , Benzopiranos/farmacocinética , Inhibidores Enzimáticos , Etanolaminas/farmacología , Etanolaminas/farmacocinética , Hemodinámica/efectos de los fármacos , Hipertensión/inducido químicamente , NG-Nitroarginina Metil Éster , Antagonistas Adrenérgicos beta/química , Animales , Área Bajo la Curva , Benzopiranos/química , Presión Sanguínea/efectos de los fármacos , Química Farmacéutica , Relación Dosis-Respuesta a Droga , Etanolaminas/química , Frecuencia Cardíaca/efectos de los fármacos , Hipertensión/metabolismo , Hipertensión/fisiopatología , Inyecciones Intravenosas , Masculino , Nebivolol , Óxido Nítrico Sintasa de Tipo I/antagonistas & inhibidores , Ratas , Ratas Wistar , EstereoisomerismoRESUMEN
An increase in blood pressure variability (BPV) contributes to the development of target organ damage associated with hypertension. Treatment with conventional ß-blockers, such as atenolol, has been associated with an increase in BPV; however, the extrapolation of these results to third generation ß-blockers with pleiotropic effects seems to be inappropriate. The cardiovascular effects of third generation ß-blockers, carvedilol and nebivolol, were assessed in sinoaortic-denervated rats (SAD) and compared with the second generation ß-blocker atenolol and the calcium channel blocker verapamil, with a special focus on short-term BPV. Male SAD rats were acutely treated with carvedilol, nebivolol, atenolol or verapamil at two different doses, and the effects on blood pressure and BPV were recorded. Short-term BPV was assessed by the s.d. of BP recordings. Beat-to-beat BPV was studied using spectral analysis to assess the vascular sympatholytic activity of carvedilol and nebivolol by estimating the effects of these drugs on the ratio of low frequency (LF) to high frequency (HF) BPV (LF/HF ratio). Nebivolol, carvedilol and the calcium channel blocker verapamil significantly attenuated short-term BPV at both doses in SAD animals, and there were no differences between the drugs. Conversely, atenolol did not modify baseline s.d. values at either dose. Carvedilol and nebivolol significantly reduced the LF/HF ratio in SAD rats compared with the effects of atenolol and verapamil, suggesting the ability of the third generation ß-blockers to reduce vascular sympathetic activity. In conclusion, third generation ß-blockers induce a marked reduction in short-term BPV in SAD rats compared to atenolol. Moreover, the ability of carvedilol and nebivolol to reduce short-term BPV in SAD rats is equivalent to that of verapamil, suggesting that these ß-blockers may have an additional beneficial effect through their control of short-term variability to a similar extent to calcium channel blockers.
Asunto(s)
Antagonistas Adrenérgicos beta/farmacología , Presión Sanguínea/efectos de los fármacos , Nodo Sinoatrial/fisiología , Animales , Presión Arterial/efectos de los fármacos , Atenolol/farmacología , Benzopiranos/farmacología , Bloqueadores de los Canales de Calcio/farmacología , Carbazoles/farmacología , Carvedilol , Desnervación , Relación Dosis-Respuesta a Droga , Etanolaminas/farmacología , Frecuencia Cardíaca/fisiología , Masculino , Nebivolol , Propanolaminas/farmacología , Ratas , Ratas Wistar , Verapamilo/farmacologíaRESUMEN
Cardiovascular effects and pharmacokinetics of nebivolol were assessed in spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) animals. Male SH and WKY rats were treated with vehicle or nebivolol 0.3, 3, or 10 mg kg(-1) (i.v.) and effects on blood pressure (BP), heart rate, and blood pressure variability (BPV) were recorded. Plasma pharmacokinetics of d- and l-nebivolol was studied by traditional blood sampling. Short-term and beat-to-beat BPV was assessed by standard deviation and spectral analysis of BP recording, respectively. Nebivolol showed enantioselective pharmacokinetics in both experimental groups; clearance of l-nebivolol was significantly greater than d-enantiomer. Clearance of nebivolol was significantly reduced in SHR with regards to WKY animals. Hypotensive response to nebivolol 3 and 10 mg kg(-1) was significantly enhanced in SHR compared with normotensive animals. Spectral analysis of beat-to-beat BPV showed a greater reduction in low frequency BPV in SHR than in WKY rats. Nebivolol 3 and 10 mg kg(-1) significantly reduced ratio low frequency/high frequency BPV only in SHR. Short-term BPV was markedly reduced by nebivolol 0.3, 3, and 10 mg kg(-1) in WKY and SHR. In conclusion, the hypertensive stage in SHR modifies nebivolol pharmacokinetic properties and enhances its hypotensive response due to a greater attenuation in vascular sympathetic activity and enhancement of endothelial-derived NO activity. Nebivolol markedly attenuates short-term BPV in both experimental groups providing beneficial cardiovascular effects by both controlling high blood pressure and its short-term variability.
Asunto(s)
Antagonistas Adrenérgicos beta/farmacología , Antihipertensivos/farmacología , Benzopiranos/farmacología , Presión Sanguínea/efectos de los fármacos , Etanolaminas/farmacología , Animales , Antihipertensivos/farmacocinética , Área Bajo la Curva , Benzopiranos/farmacocinética , Química Farmacéutica , Etanolaminas/farmacocinética , Frecuencia Cardíaca/efectos de los fármacos , Hipertensión/fisiopatología , Inyecciones Intravenosas , Masculino , Nebivolol , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , EstereoisomerismoRESUMEN
The cardiovascular effects and pharmacokinetics of carvedilol were assessed in spontaneously hypertensive (SH) and Wistar Kyoto (WKY) animals with special focus on short-term blood pressure variability (BPV). Male SH and WKY rats were acutely treated with vehicle or carvedilol 1 or 5 mg kg(-1) (i.v.), and effects on blood pressure (BP), heart rate (HR) and BPV were recorded. Plasma pharmacokinetics of R- and S-carvedilol was studied by traditional blood sampling. Relationship between carvedilol concentrations and their hypotensive and bradycardic effects was established by pharmacokinetic-pharmacodynamic (PK-PD) modelling. Short-term BPV was assessed by standard deviation of BP recording. Vascular sympatholytic activity of carvedilol was studied by estimation of drug effects on ratio between low frequency (LF) and high frequency (HF) BPV (LF/HF ratio). Although pharmacokinetic properties of carvedilol remained mainly unaffected in SH rats with regard to WKY rats, hypertensive animals showed a reduction in drug clearance of R- and S-carvedilol after administration of 1 mg kg(-1) compared with WKY rats. PK-PD analysis of HR changes induced by S-carvedilol showed a greater maximal bradycardic response to carvedilol in SH rats (E (max), -27.6 ± 3.9%; p < 0.05) compared with WKY group (E (max), -13.4 ± 2.5%). SH rats showed a greater hypotensive effect of racemic carvedilol (E (max), -45.5 ± 5.0%; p < 0.05) with regard to WKY group (E (max), -17.9 ± 4.5%). Carvedilol induced a greater reduction of LF/HF ratio in SH rats compared with WKY rats. Short-term BPV was markedly reduced by carvedilol in WKY and SH rats. In conclusion, as a consequence of an enhanced bradycardic response and a greater vascular sympatholytic activity, carvedilol exerts a greater hypotensive response in SH rats compared with WKY animals and dramatically reduces short-term BPV.