Assessment of the Diuretic Properties of Rice Bean Accessions Using a Mouse Model and Identification of Active Polyphenolic Compounds.

Rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi], an annual legume in the genus Vigna, is a promising crop suitable for cultivation in a changing climate to ensure food security. It is also a medicinal plant widely used in traditional Chinese medicine; however, little is known about the medicinal compounds in rice bean. In this study, we assessed the diuretic effect of rice bean extracts on mice as well as its relationship with the contents of eight secondary metabolites in seeds. Mice gavaged with rice bean extracts from yellow and black seeds had higher urinary output (5.44-5.47 g) and water intake (5.8-6.3 g) values than mice gavaged with rice bean extracts from red seeds. Correlation analyses revealed significant negative correlations between urine output and gallic acid (R = -0.70) and genistein (R = -0.75) concentrations, suggesting that these two polyphenols negatively regulate diuresis. There were no obvious relationships between mice diuresis-related indices (urine output, water intake, and weight loss) and rutin or catechin contents, although the concentrations of both of these polyphenols in rice bean seeds were higher than the concentrations of the other six secondary metabolites. Our study findings may be useful for future research on the diuretic effects of rice bean, but they should be confirmed on the basis of systematic medical trials.

Urea transporter UT-A1 as a novel drug target for hyponatremia.

Hyponatremia is the most common disorder of electrolyte imbalances. It is necessary to develop new type of diuretics to treat hyponatremia without losing electrolytes. Urea transporters (UT) play an important role in the urine concentrating process and have been proved as a novel diuretic target. In this study, rat and mouse syndromes of inappropriate antidiuretic hormone secretion (SIADH) models were constructed and analyzed to determine if UTs are a promising drug target for treating hyponatremia. Experimental results showed that 100 mg/kg UT inhibitor 25a significantly increased serum osmolality (from 249.83 ± 5.95 to 294.33 ± 3.90 mOsm/kg) and serum sodium (from 114 ± 2.07 to 136.67 ± 3.82 mmol/L) respectively in hyponatremia rats by diuresis. Serum chemical examination showed that 25a neither caused another electrolyte imbalance nor influenced the lipid metabolism. Using UT-A1 and UT-B knockout mouse SIADH model, it was found that serum osmolality and serum sodium were lowered much less in UT-A1 knockout mice than in UT-B knockout mice, which suggest UT-A1 is a better therapeutic target than UT-B to treat hyponatremia. This study provides a proof of concept that UT-A1 is a diuretic target for SIADH-induced hyponatremia and UT-A1 inhibitors might be developed into new diuretics to treat hyponatremia.

Pharmacological Research Progress of Novel Antihypertensive Drugs.

Cardiovascular disease stands as the leading cause of death globally, with hypertension emerging as an independent risk factor for its development. The worldwide prevalence of hypertension hovers around 30%, encompassing a staggering 1.2 billion patients, and continues to escalate annually. Medication plays a pivotal role in managing hypertension, not only effectively regulating blood pressure (BP) but also substantially mitigating the occurrence of cardiovascular and cerebrovascular diseases. This review comprehensively outlines the categories, mechanisms, clinical applications, and drawbacks of conventional antihypertensive drugs. It delves into the five primary pharmacological classifications, namely ß-receptor blockers, calcium channel blockers (CCBs), angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), and diuretics. The emphasis is placed on elucidating the mechanisms, advantages, and research progress of novel antihypertensive drugs targeting emerging areas. These include mineralocorticoid receptor antagonists (MRAs), atrial natriuretic peptides (ANPs), neutral endopeptidase inhibitors (NEPIs), sodium-dependent glucose transporter 2 inhibitors (SGLT-2Is), glucagon-like peptide-1 receptor agonists (GLP-1RAs), endothelin receptor antagonists (ERAs), soluble guanylate cyclase (sGC) agonists, brain aminopeptidase A inhibitors (APAIs), and small interfering ribonucleic acids (siRNAs) targeting hepatic angiotensinogen. Compared to conventional antihypertensive drugs, these novel alternatives exhibit favorable antihypertensive effects with minimal adverse reactions. This review serves as a valuable reference for future research and the clinical application of antihypertensive drugs.

Evaluation of renal sodium handling in heart failure with preserved ejection fraction: A pilot study.

The pathophysiology behind sodium retention in heart failure with preserved ejection fraction (HFpEF) remains poorly understood. We hypothesized that patients with HFpEF have impaired natriuresis and diuresis in response to volume expansion and diuretic challenge, which is associated with renal hypo-responsiveness to endogenous natriuretic peptides. Nine HFpEF patients and five controls received saline infusion (0.25 mL/kg/min for 60 min) followed by intravenous furosemide (20 mg or home dose) 2 h after the infusion. Blood and urine samples were collected at baseline, 2 h after saline infusion, and 2 h after furosemide administration; urinary volumes were recorded. The urinary cyclic guanosine monophosphate (ucGMP)/plasma B-type NP (BNP) ratio was calculated as a measure of renal response to endogenous BNP. Wilcoxon rank-sum test was used to compare the groups. Compared to controls, HFpEF patients had reduced urine output (2480 vs.3541 mL; p = 0.028), lower urinary sodium excretion over 2 h after saline infusion (the percentage of infused sodium excreted 12% vs. 47%; p = 0.003), and a lower baseline ucGMP/plasma BNP ratio (0.7 vs. 7.3 (pmol/mL)/(mg/dL)/(pg/mL); p = 0.014). Patients with HFpEF had impaired natriuretic response to intravenous saline and furosemide administration and lower baseline ucGMP/plasma BNP ratios indicating renal hypo-responsiveness to NPs.

Effects of thiazides and new findings on kidney stones and dysglycemic side effects.

Thiazide and thiazide-like diuretics (thiazides) belong to the most frequently prescribed drugs worldwide. By virtue of their natriuretic and vasodilating properties, thiazides effectively lower blood pressure and prevent adverse cardiovascular outcomes. In addition, through their unique characteristic of reducing urine calcium, thiazides are also widely employed for the prevention of kidney stone recurrence and reduction of bone fracture risk. Since their introduction into clinical medicine in the early 1960s, thiazides have been recognized for their association with metabolic side effects, particularly impaired glucose tolerance, and new-onset diabetes mellitus. Numerous hypotheses have been advanced to explain thiazide-induced glucose intolerance, yet underlying mechanisms remain poorly defined. Regrettably, the lack of understanding and unpredictability of these side effects has prompted numerous physicians to refrain from prescribing these effective, inexpensive, and widely accessible drugs. In this review, we outline the pharmacology and mechanism of action of thiazides, highlight recent advances in the understanding of thiazide-induced glucose intolerance, and provide an up-to-date discussion on the role of thiazides in kidney stone prevention.

Effects of sex and hydration status on kappa opioid receptor-mediated diuresis in rats.

Understanding the function of the kappa opioid receptor (KOP) is crucial for the development of novel therapeutic interventions that target KOP for the treatment of pain, stress-related disorders and other indications. Activation of KOP produces diuretic effects in rodents and man. Sex is a vital factor to consider when assessing drug response in pre-clinical and clinical studies. In this study, the diuretic effect of the KOP agonist, U50488 (1-10 mg/kg), was investigated in both adult female and male Wistar rats that were either normally hydrated or water-loaded. The KOP antagonist norbinaltorphimine (norBNI, 10 mg/kg) was administered 24 h prior to U50488 to confirm the involvement of KOP. U50488 elicited a significant diuretic response at doses ≥ 3 mg/kg in both female and male rats independent of hydration status. U50488 diuretic effects were inhibited by norBNI pre-administration. Water-loading reduced data variability for urine volume in males, but not in females, compared with normally hydrated rats. Sex differences were also evident in U50488 eliciting a significant increase in sodium and potassium ion excretion only in males. This may suggest different mechanisms of U50488 diuretic action in males where renal excretion mechanisms are directly affected more than in females.

Evaluation and estimation of diuretic activity of the linalyl acetate in the rats.

This study aimed to explore the diuretic activity of linalyl acetate (LA). LA is an essential oil, it is an integral phyto-constituent of various plants. In this study, acute and chronic diuretic activities were explored by measuring the levels of different electrolytes and pH in the urine of experimental rats. Rats were divided into five groups. The control group was given 10 mg/kg normal saline, the treated group was given 10 mg/kg furosemide, and the remaining 3 groups received different doses of LA including 25, 50, and 75 mg/kg through intraperitoneal route, to determine its diuretic potential. Urine volume for acute diuretic activity was measured for 6 hours however for chronic diuretic activity was measured for 6 days. For a comparative study of LA with a control group and treated group with reference drug, diuretic index was used. Moreover, the underlying mechanism of the diuretic activity was also explored by comparing atropine, L-NAME, and indomethacin. The results of each group with 6 rats in each group were obtained by ± standard error of the mean of every group. Analysis of Variance (ANOVA) was used for statistical analysis. Results revealed that the LA 75 mg/kg dose showed comparable results as of furosemide. Moreover, this study revealed the involvement of muscarinic receptors to produce diuresis in comparison with atropine with very little involvement of prostanoids and no effect on NO pathway induced by indomethacin and L-NAME respectively. It is concluded that LA possess anti-diuretic potential. Muscarinic receptors might be involved in producing diuretic effects.

Effects of furosemide, acetazolamide and amiloride on renal cortical and medullary tissue oxygenation in non-anaesthetised healthy sheep.

It has been proposed that diuretics can improve renal tissue oxygenation through inhibition of tubular sodium reabsorption and reduced metabolic demand. However, the impact of clinically used diuretic drugs on the renal cortical and medullary microcirculation is unclear. Therefore, we examined the effects of three commonly used diuretics, at clinically relevant doses, on renal cortical and medullary perfusion and oxygenation in non-anaesthetised healthy sheep. Merino ewes received acetazolamide (250 mg; n = 9), furosemide (20 mg; n = 10) or amiloride (10 mg; n = 7) intravenously. Systemic and renal haemodynamics, renal cortical and medullary tissue perfusion and P O 2 ${P_{{{\mathrm{O}}_{\mathrm{2}}}}}$ , and renal function were then monitored for up to 8 h post-treatment. The peak diuretic response occurred 2 h (99.4 ± 14.8 mL/h) after acetazolamide, at which stage cortical and medullary tissue perfusion and P O 2 ${P_{{{\mathrm{O}}_{\mathrm{2}}}}}$ were not significantly different from their baseline levels. The peak diuretic response to furosemide occurred at 1 h (196.5 ± 12.3 mL/h) post-treatment but there were no significant changes in cortical and medullary tissue oxygenation during this period. However, cortical tissue P O 2 ${P_{{{\mathrm{O}}_{\mathrm{2}}}}}$ fell from 40.1 ± 3.8 mmHg at baseline to 17.2 ± 4.4 mmHg at 3 h and to 20.5 ± 5.3 mmHg at 6 h after furosemide administration. Amiloride did not produce a diuretic response and was not associated with significant changes in cortical or medullary tissue oxygenation. In conclusion, clinically relevant doses of diuretic agents did not improve regional renal tissue oxygenation in healthy animals during the 8 h experimentation period. On the contrary, rebound renal cortical hypoxia may develop after dissipation of furosemide-induced diuresis.

Predicting sex differences in the effects of diuretics in renal epithelial transport during angiotensin II-induced hypertension.

Chronic angiotensin II (ANG II) infusion is an experimental model that induces hypertension in rodents. The natriuresis, diuresis, and blood pressure responses differ between males and females. This is perhaps not unexpected, given the rodent kidney, which plays a key role in blood pressure regulation, exhibits marked sex differences. Under normotensive conditions, compared with males, the female rat nephron exhibits lower Na+/H+ exchanger 3 (NHE3) activity along the proximal tubule but higher Na+ transporter activities along the distal segments. ANG II infusion-induced hypertension induces a pressure natriuretic response that reduces NHE3 activity and shifts Na+ transport capacity downstream. The goals of this study were to apply a computational model of epithelial transport along a rat nephron 1) to understand how a 14-day ANG II infusion impacts segmental electrolyte transport in male and female rat nephrons and 2) to identify and explain any sex differences in the effects of loop diuretics, thiazide diuretics, and K+-sparing diuretics. Model simulations suggest that the NHE3 downregulation in the proximal tubule is a major contributor to natriuresis and diuresis in hypertension, with the effects stronger in males. All three diuretics are predicted to induce stronger natriuretic and diuretic effects under hypertension compared with normotension, with relative increases in sodium excretion higher in hypertensive females than in males. The stronger natriuretic responses can be explained by the downstream shift of Na+ transport load in hypertension and by the larger distal transport load in females, both of which limit the ability of the distal segments to further elevate their Na+ transport.NEW & NOTEWORTHY Sex differences in the prevalence of hypertension are found in human and animal models. The kidney, which regulates blood pressure, exhibits sex differences in morphology, hemodynamics, and membrane transporter distributions. This computational modeling study provides insights into how the sexually dimorphic responses to a 14-day angiotensin II infusion differentially impact segmental electrolyte transport in rats. Simulations of diuretic administration explain how the natriuretic and diuretic effects differ between normotension and hypertension and between the sexes.

Diferencias en función del sexo en las características clínicas y resultados del ensayo clínico CLOROTIC (combinación de diuréticos de asa con tiazidas en la insuficiencia cardiaca descompensada) / Sex differences in clinical characteristics and outcomes in the CLOROTIC (combining loop with thiazide diuretics for decompensated heart failure) trial

ObjetivoEvaluar si existen diferencias en los resultados del ensayo clínico CLOROTIC según el sexo. Métodos Subanálisis del ensayo CLOROTIC, que evaluó la eficacia y la seguridad de añadir hidroclorotiazida (HCTZ) o placebo a furosemida intravenosa en pacientes con insuficiencia cardiaca aguda (ICA). Los resultados primarios y secundarios incluyeron cambios en el peso y la disnea a las 72 y 96horas, medidas de la respuesta diurética y la mortalidad y reingresos a los 30 y 90días. Se evaluó la influencia del sexo en los resultados primarios y secundarios y de seguridad. Resultados De los 230 pacientes incluidos, 111 (48%) eran mujeres, que tenían más edad y valores más elevados de fracción de eyección ventricular izquierda. Los hombres tenían más cardiopatía isquémica, enfermedad pulmonar obstructiva crónica y mayor valor de péptidos natriuréticos. La adición de HCTZ a furosemida se asoció con una mayor pérdida de peso a las 72/96horas y mejor respuesta diurética a las 24horas en comparación con el placebo, sin diferencias significativas según el sexo (ningún valor de p para la interacción fue significativo). El deterioro de la función renal fue más frecuente en mujeres (OR: 8,68; IC95%: 3,41-24,63) que en varones (OR: 2,5; IC95%: 0,99-4,87), p=0,027. No hubo diferencias en la mortalidad ni en los reingresos a los 30/90días. Conclusión La adición de HCTZ a furosemida intravenosa es una estrategia eficaz para mejorar la respuesta diurética en la ICA sin diferencias según el sexo. Sin embargo, el deterioro de la función renal es más frecuente en las mujeres. (AU)

Aims The addition of hydrochlorothiazide (HCTZ) to furosemide improved the diuretic response in patients with acute heart failure (AHF) in the CLOROTIC trial. Our aim was to evaluate if there were differences in clinical characteristics and outcomes according to sex. Methods This is a post hoc analysis of the CLOROTIC trial, including 230 patients with AHF randomized to receive HCTZ or placebo in addition to an intravenous furosemide regimen. The primary and secondary outcomes included changes in weight and patient-reported dyspnoea 72 and 96h after randomization, metrics of diuretic response and mortality/rehospitalizations at 30 and 90days. The influence of sex on primary, secondary and safety outcomes was evaluated. Results One hundred and eleven (48%) women were included in the study. Women were older and had higher values of left ventricular ejection fraction. Men had more ischemic cardiomyopathy and chronic obstructive pulmonary disease and higher values of natriuretic peptides. The addition of HCTZ to furosemide was associated to a greatest weight loss at 72/96h, better metrics of diuretic response and higher 24-h diuresis compared to placebo without significant differences according to sex (all P-values for interaction were not significant). Worsening renal function occurred more frequently in women (OR: 8.68; 95%CI: 3.41-24.63) than men (OR: 2.5; 95%CI: 0.99-4.87), P=.027. There were no differences in mortality or rehospitalizations at 30/90days. Conclusion Adding HCTZ to intravenous furosemide is an effective strategy to improve diuretic response in AHF with no difference according to sex, but worsening renal function was more frequent in women. (AU)

Diferencias en función del sexo en las características clínicas y resultados del ensayo clínico CLOROTIC (combinación de diuréticos de asa con tiazidas en la insuficiencia cardiaca descompensada) / Sex differences in clinical characteristics and outcomes in the CLOROTIC (combining loop with thiazide diuretics for decompensated heart failure) trial

ObjetivoEvaluar si existen diferencias en los resultados del ensayo clínico CLOROTIC según el sexo. Métodos Subanálisis del ensayo CLOROTIC, que evaluó la eficacia y la seguridad de añadir hidroclorotiazida (HCTZ) o placebo a furosemida intravenosa en pacientes con insuficiencia cardiaca aguda (ICA). Los resultados primarios y secundarios incluyeron cambios en el peso y la disnea a las 72 y 96horas, medidas de la respuesta diurética y la mortalidad y reingresos a los 30 y 90días. Se evaluó la influencia del sexo en los resultados primarios y secundarios y de seguridad. Resultados De los 230 pacientes incluidos, 111 (48%) eran mujeres, que tenían más edad y valores más elevados de fracción de eyección ventricular izquierda. Los hombres tenían más cardiopatía isquémica, enfermedad pulmonar obstructiva crónica y mayor valor de péptidos natriuréticos. La adición de HCTZ a furosemida se asoció con una mayor pérdida de peso a las 72/96horas y mejor respuesta diurética a las 24horas en comparación con el placebo, sin diferencias significativas según el sexo (ningún valor de p para la interacción fue significativo). El deterioro de la función renal fue más frecuente en mujeres (OR: 8,68; IC95%: 3,41-24,63) que en varones (OR: 2,5; IC95%: 0,99-4,87), p=0,027. No hubo diferencias en la mortalidad ni en los reingresos a los 30/90días. Conclusión La adición de HCTZ a furosemida intravenosa es una estrategia eficaz para mejorar la respuesta diurética en la ICA sin diferencias según el sexo. Sin embargo, el deterioro de la función renal es más frecuente en las mujeres. (AU)

Aims The addition of hydrochlorothiazide (HCTZ) to furosemide improved the diuretic response in patients with acute heart failure (AHF) in the CLOROTIC trial. Our aim was to evaluate if there were differences in clinical characteristics and outcomes according to sex. Methods This is a post hoc analysis of the CLOROTIC trial, including 230 patients with AHF randomized to receive HCTZ or placebo in addition to an intravenous furosemide regimen. The primary and secondary outcomes included changes in weight and patient-reported dyspnoea 72 and 96h after randomization, metrics of diuretic response and mortality/rehospitalizations at 30 and 90days. The influence of sex on primary, secondary and safety outcomes was evaluated. Results One hundred and eleven (48%) women were included in the study. Women were older and had higher values of left ventricular ejection fraction. Men had more ischemic cardiomyopathy and chronic obstructive pulmonary disease and higher values of natriuretic peptides. The addition of HCTZ to furosemide was associated to a greatest weight loss at 72/96h, better metrics of diuretic response and higher 24-h diuresis compared to placebo without significant differences according to sex (all P-values for interaction were not significant). Worsening renal function occurred more frequently in women (OR: 8.68; 95%CI: 3.41-24.63) than men (OR: 2.5; 95%CI: 0.99-4.87), P=.027. There were no differences in mortality or rehospitalizations at 30/90days. Conclusion Adding HCTZ to intravenous furosemide is an effective strategy to improve diuretic response in AHF with no difference according to sex, but worsening renal function was more frequent in women. (AU)

Clinical effect of torsemide in a horse with congestive heart failure and atrial fibrillation.

In this case report, a high dose of torsemide (6mg/kg, every 12 hours for 3 days followed by 12mg/kg, every 12 hours for 4 days) was administered orally to a horse with congestive heart failure (CHF) and atrial fibrillation. Blood samples for measurement of plasma torsemide concentrations were obtained one hour after each drug administration. Pharmacodynamic effects of oral torsemide were evaluated by daily physical examination, electrocardiography, and serum biochemistry. The horse tolerated administration of torsemide. A decrease in ventral oedema and venous congestion was subjectively noted at day 7. Torsemide plasma concentration markedly increased at day 5 (peak concentration of 15.41 µg/mL). Evidence of an increase in renal markers was observed throughout the study period. Electrolyte measurements revealed mild hyponatremia and hypochloremia, and moderate hypokalaemia. No electrocardiographic changes related to torsemide administration were observed. After seven days of treatment, the horse was euthanised due to his disease stage and poor prognosis. Results indicate that torsemide was absorbed after oral administration and was well tolerated in this horse. Furthermore, clinical improvement in this single case indicates that torsemide might be utilized as an oral alternative to furosemide in the management of equine patients in CHF. The high doses of torsemide used in this case report should be reserved for cases without clinical response to lower doses and with close monitoring of electrolytes and renal function parameters. Further investigation of torsemide clinical efficacy and safety in horses with CHF with a larger cohort and prolonged administration is warranted.

3-Demethyl-2-geranyl-4-prenylbellidifoline, a natural xanthone with diuretic and kidney protective properties.

OBJECTIVES: The diuretic and kidney protective effect of the 3-demethyl-2-geranyl-4-prenylbellidifoline (DGP) were evaluated in rats. METHODS: The normotensive (NTR) and spontaneously hypertensive rats (SHR) received, once a day for 7 days, oral treatment with DGP (0.1 mg/kg), hydrochlorothiazide (10 mg/kg), or vehicle (10 ml/kg). Urine, blood, and kidney samples were collected for further analysis. KEY FINDINGS: The urine and Na+ elimination content were significantly higher in the groups that received DGP. Furthermore, a Ca2+-sparing action was detected in the urine of DGP-treated groups, which was consistent with the reduction in calcium oxalate crystal formation. Relevantly, the treatment did not change the parameters examined in the blood. Concerning the renal analyses, DGP treatment recovered the morphological damages of the kidney corpuscle area of SHR. In addition to the differences observed between the NTR and SHR vehicle groups, DGP augmented the amount of reduced glutathione and the activity of glutathione S-transferase GST while reducing the catalase and N-acetyl-ß-D-glucosaminidase activity and nitrite levels. CONCLUSION: Together, this study displayed the prolonged diuretic action of DGP and its natriuretic, Ca2+-sparing, and antiurolytic effects. The antioxidative and anti-inflammatory effects of DGP were evidenced in SHR kidneys, opening perspectives for further studies regarding the benefits of this xanthone.

Hypertensive rats show increased renal excretion and decreased tissue concentrations of glycine betaine, a protective osmolyte with diuretic properties.

Hypertension leads to water-electrolyte disturbances and end-organ damage. Betaine is an osmolyte protecting cells against electrolyte imbalance and osmotic stress, particularly in the kidneys. This study aimed to evaluate tissue levels and hemodynamic and renal effects of betaine in normotensive and hypertensive rats. Betaine levels were assessed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) in normotensive rats (Wistar-Kyoto, WKYs) and Spontaneously Hypertensive rats (SHRs), a model of genetic hypertension. Acute effects of IV betaine on blood pressure, heart rate, and minute diuresis were evaluated. Gene and protein expression of chosen kidney betaine transporters (SLC6a12 and SLC6a20) were assessed using real-time PCR and Western blot. Compared to normotensive rats, SHRs showed significantly lower concentration of betaine in blood serum, the lungs, liver, and renal medulla. These changes were associated with higher urinary excretion of betaine in SHRs (0.20 ± 0.04 vs. 0.09 ± 0.02 mg/ 24h/ 100g b.w., p = 0.036). In acute experiments, betaine increased diuresis without significantly affecting arterial blood pressure. The diuretic response was greater in SHRs than in WKYs. There were no significant differences in renal expression of betaine transporters between WKYs and SHRs. Increased renal excretion of betaine contributes to decreased concentration of the protective osmolyte in tissues of hypertensive rats. These findings pave the way for studies evaluating a causal relation between depleted betaine and hypertensive organ damage, including kidney injury.

Resistant hypertension: challenges in everyday practice.

Resistant hypertension is defined as not achieving sufficient control of blood pressure (BP), that is, maintaining BP values equal to or above 140/90 mm Hg when using 3 antihypertensive drugs, including diuretics, properly combined and at maximum doses. The uncontrolled treated hypertension should be confirmed in out­of­office BP measurements, preferably with 24­hour ambulatory BP monitoring. Demographic and clinical characteristics indicate that patients with resistant hypertension are older than the general population of patients with arterial hypertension and more often suffer from comorbidities. When resistant hypertension is suspected, it is necessary to assess whether optimal pharmacotherapy has been prescribed, including appropriate combinations of antihypertensive drugs and diuretics at appropriate doses. It is also important to exclude parallel use of drugs that may have unfavorable interactions leading to an increase in BP. A common cause of pseudoresistant hypertension is a patient's failure to comply with therapeutic recommendations, including a lack of lifestyle changes and nonadherence to the prescribed medication regimen. An important step in management of resistant hypertension is targeted screening with diagnostic tests for secondary hypertension. Expanding of the drug therapy beyond a 3­drug regimen should include a mineralocorticoid receptor antagonist, in particular spironolactone. In selected patients, device­based hypertension treatment might be considered.

Diuretic, Natriuretic, And Ca2+-Sparing Effect Of The Alkaloid Boldine In Rats.

BACKGROUND: Previous studies indicate the renal vasodilating effects of boldine, an alkaloid found in Peumus boldus. However, its potential to induce diuresis still needs to be studied. METHODS: Wistar rats were used and the urine volume was noted for 8 h and further studied. RESULTS: The acute treatment at 0.1 and 0.3 mg/kg of boldine showed a diuretic, natriuretic, and Ca2+-sparing effect in rats without changing the urinary elimination of K+and Cl-. When boldine was given in combination with hydrochlorothiazide, there was an increase in urinary volume compared to the vehicle group. However, this was not different from the treatments in its isolated form. Urine Ca2+values ​​remained low but were not enhanced by this association. The excretion of Na+and Cl- was significantly increased compared to the group that received only vehicle or boldine. On the other hand, although the association of amiloride plus boldine did not result in a diuretic effect, the increase in Na+and the reduction in K+excretion were significantly potentiated. Furthermore, in the presence of the non-selective muscarinic receptor antagonist atropine, boldine showed reduced capacity to increase urinary volume, maintaining the natriuretic and Ca2+-sparing effect, besides a very evident K+-sparing action. Similar results were obtained in the presence of the non-selective cyclooxygenase inhibitor indomethacin. Furthermore, boldine showed an ex vivo antiurolithiasis activity, reducing calcium oxalate's precipitation and crystallization. CONCLUSIONS: This study reveals the diuretic, natriuretic, Ca2+-sparing, and antiurolithiatic effects of boldine, an action possibly related to muscarinic receptor activation and prostanoid generation.