Long-lasting Antihypertensive Effect Research Articles

NO-cGMP-K+ Channels Pathways Participate in the Antihypertensive Effects of Attalea phalerata Martius ex Spreng Oil-Loaded Nanocapsules.

Attalea phalerata Martius ex Spreng is a palm tree that is widely distributed in the Central-West region of Brazil. In this study, we investigated whether the oil-loaded nanocapsules of A. phalerata (APON) have acute and long-lasting antihypertensive effects in male spontaneously hypertensive rats (SHR), as well as explored the underlying molecular mechanisms. APON was prepared using the interfacial polymer deposition method. The particle size, polydispersity index, and zeta potential were investigated using dynamic and electrophoretic light scattering. The antihypertensive effects of APON (administered at doses of 1, 3, and 10 mg/kg) were evaluated after acute intraduodenal administration and after 7 days of oral treatment. To investigate the molecular pathways involved, we used pharmacological antagonists and inhibitors that target prostaglandin/cyclic adenosine monophosphate, nitric oxide/cyclic guanosine monophosphate, and potassium channels. Both acute and prolonged administration of APON (at doses of 3 and 10 mg/kg) resulted in a significant reduction in systolic, diastolic, and mean arterial pressure. Prior treatment with a non-selective nitric oxide synthase inhibitor (Nω-nitro-L-arginine methyl ester), guanylyl cyclase inhibitor (methylene blue), or non-selective calcium-sensitive K+ channel blocker (tetraethylammonium) abolished the antihypertensive effects of APON. Our study showed that A. phalerata oil-loaded nanocapsules have a significant antihypertensive effect in SHR after both short-term and long-term (7-day) use. This effect seems to rely on the vascular endothelium function and involves the NO-cGMP-K+ channel pathway. This research suggests a new direction for future studies to definitively prove the therapeutic benefits of APON in treating cardiovascular disease.

Marine sourced tripeptide SRP and its sustained-release formulation SRP-PLGA-MS exhibiting antihypertensive effect in spontaneously hypertensive rats and HUVECs.

Biopeptides from Sipunculus nudus were reported with good ACE inhibitory activity, and the tripeptide SRP was one with the highest ACE inhibition rate. However, the disadvantage of short half-life limited the development of peptide drugs. Moreover, the distinct mechanism of the peptide inhibiting ACE remained unknown. Thus, in this study, a sustained release formulation of SRP-PLGA-MS was designed and prepared. Its long-lasting antihypertensive effect as well as improvement of vascular pathomorphology was verified in spontaneously hypertensive rat (SHR). In addition, the anti-oxidant activity of SRP in human umbilical vein endothelial cells (HUVECs) was evaluated. The results showed that SRP inhibited the production of ROS and NO, which involve the NADPH oxidase, and Keap1/Nrf2 signaling pathway. This study demonstrated that SRP-PLGA-MS had the potential to develop sustained-release drugs for hypertension treatment.

Predictors of antihypertensive efficiency of renal denervation in patients with resistant hypertension and type 2 diabetes mellitus

Abstract Background Currently, one of the actively studied interventional methods for the treatment of resistant hypertension (RHTN) is renal denervation (RDN). Despite the safety of the procedure and the long-lasting antihypertensive effect, a significant decrease in systolic blood pressure (SBP) ≥10 mmHg is observed only in 60–80% of patients. According to the Global SYMPLICITY Registry (GSR) study, patients with diabetes mellitus could benefit from lower blood pressure after renal denervation due to initially higher sympathetic activity. The indicators associated with the processes of sympathetic hyperactivation include impaired diastolic function and total peripheral resistance (TPR), reflecting the resistance of arterioles (resistive vessels) to blood flow. Purpose To identify predictors of the antihypertensive efficacy of renal denervation in patients with RHTN and type 2 diabetes mellitus (DM) based on the results of a six-month follow-up. Methods The study included 36 patients with RHTN and type 2 diabetes mellitus (DM) (mean age 61,4±6,4 years, 14 men, mean 24-hour (24-hr) blood pressure (BP) (systolic/diastolic) 158,6±15,2/79,8±12,7 mmHg, mean HbA1c 7,2±1,2%). The prospective interventional study with renal denervation (NCT02667912 and NCT01499810 at ClinicalTrial.gov) enrolled 30 patients. Office BP and ABPM, diastolic function and TPR assessment were performed in all patients at baseline and 6 months after RDN. 29 patients completed 6-month follow-up. Results RDN led to a significant reduction in systolic and diastolic 24-hr BP (−10.9/−5.7 mmHg, p=0.002/0.003). Depending on the degree of decrease in 24-hr systolic BP, the patients were retrospectively divided into 2 groups: “responders” (persons with a decrease in 24-hr SBP by 10 or more mmHg) and “non-responders” (with a lesser degree of decrease in 24-hr SBP). The proportion of respondents to the intervention was 48.3%. Initially, the group of “responders” differed from the group of “non-responders” by higher average E/e' values (15.1 and 11.9, respectively, p=0.049) and TPR indicators (2.39±0.45 and 1.93±0.35 dyn s cm–5, respectively, p=0.003). These indicators were included in a logistic model to predict the antihypertensive efficacy of renal denervation. The sensitivity was 78.6% (11 correct predictions out of 14 cases), specificity – 80% (12 correct predictions out of 15 cases), (p=0.020). Conclusion Estimation of the total peripheral resistance and the average ratio E/e' allows predicting the antihypertensive efficacy of renal denervation in patients with resistant hypertension and type 2 diabetes mellitus. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Russian Foundation for Basic Research

A milk-derived pentapeptide reduces blood pressure in advanced hypertension in a CCK system-dependent manner.

We recently found that a peptide that activates the cholecystokinin (CCK) system effectively reduces blood pressure in spontaneously hypertensive rats (SHR) after the development of hypertension, after which hypotensive drugs are sometimes less effective. In this study, we investigated the vasorelaxation and antihypertensive effects of a peptide derived from a milk protein in SHR with advanced hypertension. The vasorelaxing activity was measured using the mesenteric artery isolated from SHR and the systemic blood pressure was measured by the tail-cuff method. KFWGK was released from bovine serum albumin (BSA) and the model peptide after subtilisin digestion. KFWGK relaxed the mesenteric artery and this vasorelaxation activity was inhibited by lorglumide, an antagonist of the CCK1 receptor. KFWGK more potently relaxed the artery from advanced-stage SHR than that from early-stage SHR. Orally administered KFWGK exhibited potent and long-lasting antihypertensive effects in SHR after the development of hypertension (the minimum effective dose was 5 μg kg-1). The KFWGK-induced antihypertensive effects were also blocked by a CCK antagonist, suggesting that it activates the CCK system. In conclusion, KFWGK, a CCK-dependent vasorelaxant peptide, exhibited potent antihypertensive effects in SHR after the development of hypertension.

Strong and Sustained Antihypertensive Effect of Small Interfering RNA Targeting Liver Angiotensinogen

Small interfering RNAs (siRNAs) targeting hepatic angiotensinogen ( Agt) may provide long-lasting antihypertensive effects, but the optimal approach remains unclear. Here, we assessed the efficacy of a novel AGT siRNA in spontaneously hypertensive rats. Rats were treated with vehicle, siRNA (10 mg/kg fortnightly; subcutaneous), valsartan (31 mg/kg per day; oral), captopril (100 mg/kg per day; oral), valsartan+siRNA, or captopril+valsartan for 4 weeks (all groups, n=8). Mean arterial pressure (recorded via radiotelemetry) was lowered the most by valsartan+siRNA (-68±4 mm Hg), followed by captopril+valsartan (-54±4 mm Hg), captopril (-23±2 mm Hg), siRNA (-14±2 mm Hg), and valsartan (-10±2 mm Hg). siRNA and captopril monotherapies improved cardiac hypertrophy equally, but less than the dual therapies, which also lowered NT-proBNP (N-terminal pro-B-type natriuretic peptide). Glomerular filtration rate, urinary NGAL (neutrophil gelatinase-associated lipocalin), and albuminuria were unaffected by treatment. siRNA lowered circulating AGT by 97.9±1.0%, and by 99.8±0.1% in combination with valsartan. Although siRNA greatly reduced renal Ang (angiotensin) I, only valsartan+siRNA suppressed circulating and renal Ang II. This coincided with decreased renal sodium hydrogen exchanger type 3 and phosphorylated sodium chloride cotransporter abundances. Renin and plasma K+ increased with every treatment, but especially during valsartan+siRNA; no effects on aldosterone were observed. Collectively, these data indicate that Ang II elimination requires >99% suppression of circulating AGT. Maximal blockade of the renin-angiotensin system, achieved by valsartan+siRNA, yielded the greatest reduction in blood pressure and cardiac hypertrophy, whereas AGT lowering alone was as effective as conventional renin-angiotensin system inhibitors. Given its stable and sustained efficacy, lasting weeks, RNA interference may offer a unique approach to improving therapy adherence and treating hypertension.

Bj-PRO-5a and Bj-PRO 10c Found at C-Type Natriuretic Peptide Precursor of Bothrops jararaca Change Renal Function of Hypertensive Rats

Proline-rich oligopeptides from Bothrops jararaca (Bj-PROs) produce potent and long-lasting antihypertensive effect through mechanisms that go beyond ACE inhibition. In this study we evaluated the renal function parameters of spontaneously hypertensive rats (SHR) injected with Bj-PRO-5a and -10c (0.47, 71 or 710 nmol/kg) found in the CNP-precursor of the snake. At 71 and 710 nmol/kg, Bj-PROs increased urinary flow rate (18.1–43.5%). At 71 nmol/kg, Bj-PRO 5a and 10c elevated sodium excretion (68.1 and 40.9%, respectively) and Bj-PRO-5a also increased urinary sodium/creatinine ratio (56.5%). At 0.47 nmol/kg, Bj-PROs did not change renal function. All doses of Bj-PROs reduced blood pressure (Δ = −13 to −24mmHg). We conclude that Bj-PROs reduce blood pressure and improve renal function of SHRs through diuretic and natriuretic mechanisms.

The Immediate and Long-Lasting Antihypertensive Effects of Aerobic Versus Isometric Handgrip Exercise

The Immediate and Long-Lasting Antihypertensive Effects of Aerobic Versus Isometric Handgrip Exercise

Benefits of delapril in hypertensive patients along the cardiovascular continuum

Angiotensin-converting enzyme inhibitors (ACEIs) are the first-line therapy for the treatment of hypertension. However, not all ACEIs are equal. Delapril is a nonsulfhydryl ACEI with unique properties. Delapril has a high lipophilicity and weak bradykinin potentiating action. As a result, delapril has a more potent inhibition capacity of vascular wall angiotensin-converting enzyme activity and a lower incidence of cough than enalapril or captopril. With regard to efficacy, delapril has a long-lasting antihypertensive effect with a trough/peak ratio that is in the upper range of different ACEIs and a positively high smoothness index. Thus, delapril effectively and smoothly reduces blood pressure over 24 h. Moreover, the benefits of delapril are not limited to hypertensive patients, but also in those with microalbuminuria, left ventricular hypertrophy, myocardial infarction or heart failure; delapril appears to be effective and well tolerated.

Pharmacokinetic evaluation and clinical utility of azilsartan medoxomil for the treatment of hypertension

Introduction: Azilsartan medoxomil is a newly approved angiotensin-receptor blocker for the management of hypertension. It is a prodrug that is quickly hydrolyzed to the active moiety azilsartan, a potent and highly selective angiotensin-receptor blocker with estimated bioavailability of ∼ 60%. This new agent induces a potent and long-lasting antihypertensive effect. The effective therapeutic antihypertensive dosages of azilsartan medoxomil in humans vary from 40 to 80 mg/day.Areas covered: The authors review the results of clinical trials published in journals indexed in Medline, Scopus and Google Scholar. Primarily the authors discuss articles that analyze the safety and efficacy of azilsartan in lowering blood pressure.Expert opinion: Clinical trials have demonstrated that azilsartan is superior to other angiotensin-receptor blockers in lowering blood pressure. However, the clinical blood pressure trials of azilsartan published to date have been mainly conducted in patients without serious comorbidities and it is not clear if azilsartan has advantages over other angiotensin-receptor blockers in the treatment of these types of hypertensive patients. In addition, it remains to be determined whether the specific pharmacologic and pharmacokinetic characteristics of azilsartan will have a clinically significant impact on long-term cardiovascular outcomes.

New treatment options in the management of hypertension: appraising the potential role of azilsartan medoxomil

Renin–angiotensin–system (RAS) activation plays a key role in the development of hypertension and cardiovascular disease. Drugs that antagonize the RAS (angiotensin-converting enzyme [ACE] inhibitors and angiotensin receptor blockers [ARBs]) have proven clinical efficacy in reducing blood pressure values and cardiovascular morbidity and mortality. ACE inhibitors partially inhibit plasma ACE, and angiotensin II generation. Thus, ARBs, which block selectively type 1 angiotensin II receptor (AT1R), have been developed and used in the clinical management of hypertension and cardiovascular disease. Experimental and clinical trials with ARBs indicate that this class of drug represents an effective, safe and well tolerated therapeutic option for the prevention and care of hypertension, even though there is no proven superiority as compared to ACE inhibitors except for the better tolerability. Most ARBs may not completely inhibit the AT1R at the approved clinical doses. Azilsartan medoxomil is a newly approved ARB for the management of hypertension. This ARB induces a potent and long-lasting antihypertensive effect and may have cardioprotective properties. This article reviews the current evidence on the clinical effectiveness of azilsartan in hypertension.

Effects of the new angiotensin II type 1 receptor antagonist KRH-594 on several types of experimental hypertension.

The antihypertensive effect of dipotassium (Z)-2-[[5-ethyl-3-[2'-(1H- tetrazol-5-yl)biphenyl-4-yl]methyl-1,3,4-thiadiazoline-2- ylidene]aminocarbonyl]-1-cyclopentenecarboxylate (CAS 169328-25-0, KRH-594), a new angiotensin II type 1 (AT1) receptor antagonist, was studied in several experimental hypertensive models. The effects of KRH-594 on the circulating reninangiotensin system and on renal function were also investigated. Oral administration of KRH-594 (0.3 or 1 mg/kg) dose-dependently inhibited the angiotensin II-induced pressor response in common marmosets. KRH-594 (1, 3, or 10 mg/kg p.o.) dose-dependently exerted a long-lasting antihypertensive effect in spontaneously hypertensive rats (SHRs) and in 2-kidney 1-clip renal hypertensive rats (RHRs). Furthermore, repeated oral administration of KRH-594 (3 or 10 mg/kg/d) reduced blood pressure dose-dependently in SHRs, RHRs, and renal hypertensive dogs without tachycardia and with no evidence of a rebound phenomenon following drug withdrawal. On the other hand, in deoxycorticosterone acetate salt rats and normotensive rats, KRH-594 (10 or 30 mg/kg p.o.) did not have significant effects on systolic blood pressure. In SHRs, KRH-594 (3 or 10 mg/kg/d p.o. for 2 weeks) dose-dependently increased both plasma renin activity and the plasma angiotensin I concentration, but had no effect on the urinary excretion of sodium, potassium, and chloride or on creatinine clearance. These results suggest that KRH-594 should be effective in patients with essential or renal hypertension.

Relationship between plasma concentration and antihypertensive effect of the dihydropyridine calcium antagonist, benidipine, in rats.

Although benidipine hydrochloride, a hydrophobic and weakly cationic dihydropyridine calcium antagonist, has slow onset but long-lasting anti-hypertensive effect in experimental animals and man, after administration it rapidly disappears from the plasma. Correlation of the plasma concentration with reduction in blood pressure has been investigated in spontaneously hypertensive rats, and concentrations in the mesenteric artery were compared with those in plasma after oral and intravenous administration of benidipine to rats. After oral administration of benidipine to spontaneously hypertensive rats, the fall in blood pressure showed an anti-clock hysteresis phenomenon. Using concomitant analysis, plasma concentrations and anti-hypertensive activity could both be closely fitted to a one-compartment open model and the effect compartment for the pharmacological activity of benidipine could be described by a Hill equation. Concentrations in the mesenteric artery increased rapidly and then declined more slowly than in plasma. The mean residence time of benidipine in the mesenteric artery corresponded closely to the reciprocal of the rate constant for elimination of benidipine from the effect compartment. From these results it seems that benidipine is retained longer in the plasma membrane, an effective site, because of its physicochemical properties, and thus shows a more sustained anti-hypertensive effect than would be predicted from its disposition in plasma.

In Vitro Antagonistic Properties of a New Angiotensin Type 1 Receptor Blocker, Azilsartan, in Receptor Binding and Function Studies

The angiotensin II (AII) antagonistic action of azilsartan (AZL) [2-ethoxy-1-{[2'-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl}-1H-benzimidazole-7-carboxylic acid] was investigated in radioligand binding and function studies. AZL inhibited the specific binding of ¹²⁵I-Sar¹-Ile⁸-AII to human angiotensin type 1 receptors with an IC₅₀ of 2.6 nM. The inhibitory effect of AZL persisted after washout of the free compound (IC(50) value of 7.4 nM). Olmesartan, telmisartan, valsartan, and irbesartan also inhibited the specific binding with IC₅₀ values of 6.7, 5.1, 44.9, and 15.8 nM, respectively. However, their inhibitory effects were markedly attenuated with washout (IC₅₀ values of 242.5, 191.6, >10,000, and >10,000 nM). AZL also inhibited the accumulation of AII-induced inositol 1-phosphate (IP1) in the cell-based assay with an IC₅₀ value of 9.2 nmol; this effect was resistant to washout (IC₅₀ value of 81.3 nM). Olmesartan and valsartan inhibited IP1 accumulation with IC₅₀ values of 12.2 and 59.8 nM, respectively. The activities of these compounds were markedly reduced after washout (IC₅₀ value of 908.5 and 22,664.4 nM). AZL was defined as an inverse agonist in an experiment by using a constitutively active mutant of human angiotensin type 1 receptors. In isolated rabbit aortic strips, AZL reduced the maximal contractile response to AII with a pD'₂ value of 9.9. The inhibitory effects of AZL on contractile responses induced by AII persisted after the strips were washed; these inhibitory effects were more potent than those of olmesartan. These results suggest that AZL is a highly potent and slowly dissociating AII receptor blocker. Its tight receptor binding might be expected to produce potent and long-lasting antihypertensive effects in preclinical and clinical settings.

안지오텐신 수용체 리간드 KR-31125의 생체 내 활성에 관한 연구

피리딜 이미다졸 시리즈의 비펩타이드 안지오텐신 수용체 리간드로 새롭게 개발된 KR-31125에 대한 생체 내활성을 동물모델에서 검증하였다. 척수장애 동물모델에서 KR-31125는 비대칭 농도의존적으로 로자탄보다 18배 이상의 경쟁적인 혈압강하 효과를 나타내었으며, 기타 수용체 촉진제들의 영향을 받지 않았다. 안지오텐신으로 유도된 정상혈압 쥐모델에서는 대조화합물인 로자탄과 비교하여 경구효과는 동등하였으나 더 빠른 초기효과가 관찰되었다. 또한 신성고혈압 쥐모델에서 KR-31125는 로자탄보다 3배 이상의 지속형 혈압강하 효과를 나타내었고, 이뇨제를 투여하여 레닌을 활성화시킨 개실험 모델에서 KR-31125는 로자탄보다 20배 이상의 지속적인 경구혈압강하 효과를 나타내었다. 이러한 KR-31125의 생체 내 활성특징은 대사물질을 통하여 효과를 발휘하는 로자탄과 달리 동일물질의 효과에 의한 것으로 고혈압 및 혈관질환과 깊은 관련이 있는 안지오텐신 조절시스템에 대한 세포영상, 비침투성 진단등의 도구물질로서 가능성이 높을 것으로 판단된다. In vivo studies of KR-31125 (2-butyl-5-dimethoxymethyl-6-phenyl-7-methyl-3-[[2'-(1H-tetrazol-5-yl) biphenyl-4-yl]methyl]-3H-imidazo[4,5-b]pyridine) were performed in pithed rats, conscious angiotensin II (AII) challenged normotensive rats, renal hypertensive rats (RHRs) and furosemide-treated beagle dogs. KR-31125 induced a non-parallel right shift in the dose-pressor response curve to AII (<TEX>$ID_{50}$</TEX>: 0.095 mg/kg) with a dose-dependent reduction in the maximum responses in pithed rats. Compared to losartan, this antagonistic effect was about 18 times more potent, presenting competitive antagonism. Other agonists such as norepinephrine and vasopressin did not alter the responses induced by KR-31125. Orally administered KR-31125 had no agonistic effect and dose-dependently inhibited the pressor response to AII with a slightly weaker potency (<TEX>$ID_{50}$</TEX>: 0.25 and 0.47 mg/kg, respectively) in the AII-challenged normotensive rat model, but with a more rapid onset of action than losartan (time to <TEX>$E_{max}$</TEX>: 30 min for KR-31125 and 6 hr for losartan). KR-31125 produced a dose-dependent antihypertensive effect with a higher potency than losartan in RHRs, and these effects were confirmed in furosemide-treated dogs where they presented a dose-dependent and long-lasting (>8 hr) antihypertensive effect with a rapid onset of action (time to <TEX>$E_{max}$</TEX>: 2-4 hr), as well as a 20-fold greater potency than losartan. These results suggest that KR-31125 is a potent, orally active <TEX>$AT_1$</TEX> receptor antagonist that can be applied to the development of new diagnostic and research tools as an added exploratory potential of <TEX>$AT_1$</TEX> receptor antagonist.

Pharmacological characterization of KR-30988, a novel non-peptide AT1 receptor antagonist, in rat, rabbit and dog.

The pharmacological profile of KR-30988, a non-peptide AT1-selective angiotensin receptor antagonist, has been investigated by use of a variety of experimental models in-vitro and in-vivo. KR-30988 inhibited the specific binding of [125I][Sar1, Ile8]-angiotensin II to the recombinant AT1 receptor from man with a potency similar to that of losartan (IC50 values, the concentrations of drugs displacing 50% of specific binding, 13.6 and 12.3 nM, respectively), but did not inhibit the binding of [125I]CGP 42112A to recombinant AT2 receptor from man (IC50 >10 microM for both drugs). Scatchard analysis showed that KR-30988 interacted competitively with recombinant AT1 receptor from man in the same manner as losartan. In functional studies with rat and rabbit aorta, KR-30988 noncompetitively inhibited the contractile response to angiotensin II (pD2, = -log EC50 (where EC50 is the dose resulting in 50% of a reference contraction), 8.64 and 7.73, respectively) with a 20-85% decrease in the maximum contractile responses, unlike losartan. In pithed rats intravenous KR-30988 resulted in a non-parallel shift to the right of the dose-pressor response curve to angiotensin II (ID50 value, the dose inhibiting the pressor response to angiotensin II by 50%, 0.09 mg kg(-1)) with a dose-dependent reduction in the maximum responses; in this antagonistic effect KR-30988 was 20 times (approx.) more potent than losartan (ID50 1-74 mg kg(-1)). In conscious renal hypertensive rats oral administration of KR-30988 produced a dose-dependent and long-lasting (>24 h) anti-hypertensive effect; the potency was six times that of losartan (ED30 values, the dose reducing mean arterial blood pressure by 30 mmHg, 0.48 and 2.97 mg kg(-1), respectively). In conscious furosemide-treated dogs oral administration of KR-30988 produced a dose-dependent and long-lasting (>8 h) hypotensive effect with a rapid onset of action (time to Emax, the maximum effect, 1-2 h); KR-30988 was eight times more potent than losartan (ED20, the dose reducing mean arterial blood pressure by 20 mm Hg, 1.04 and 7.96 mg kg(-1), respectively). These results suggest that KR-30988 is a potent, orally active selective AT1 receptor antagonist with a mode of insurmountable antagonism.

안지오텐신 수용체 리간드 KR-31081의 생체 내 활성에 관한 연구

The pharmacological profile of KR-31081, a newly synthesized AT1 receptor antagonist, was evaluated in pithed rats, conscious renal hypertensive rats (RHRs) and conscious furosemide-treated beagle dogs. In pithed rats, KR-31081 (i.v.) induced a non-parallel right shift in the dose-pressor response curve to angiotensin II (ID50: 0.05 mg/kg) with a dose-dependent reduction in the maximum responses; this antagonistic effect was about 40 times more potent than losartan (ID50: 1.74 mg/kg) which showed competitive antagonism. KR-31081 did not alter the responses induced by other agonists such as norepinephrine and vasopressin. In RHRs, orally given KR-31081 produced a dose-dependent and long-lasting (>24 h) antihypertensive effect with a higher potency to losartan (ED20: 0.30 and 3.36 mg/kg, respectively). In furosemide-treated dogs, orally given KR-31081 produced a dose-dependent and long-lasting (>8h) antihypertensive effect with a rapid onset of action (time to Emax: 1-1.5 h) and 20-fold greater potency than losartan (ED20: 0.41 and 8.13 mg/kg, respectively). These results suggest that KR-31081 is a potent, orally active AT1 receptor antagonist useful for the research and diagnostic tools as an added exploratory potential.

Angiotensin receptor blockers in nephroprotection at patients with diabetes mellitus: focus on losartan

Many large studies have provided strong evidence that there is an association of elevated BP with a risk for cardiovascular events (CVE), such as stroke, myocardial infarction and heart failure. But none of the studies has indicated that a drug is more effective than another one in reducing the risk for CVE and death. The article summarizes the available data on ramipril in hypertensive patients of high cardiovascular risk. The results of studies demonstrate strong and long-lasting antihypertensive effect of losartan. Moreover, losartan treatment decreases cardiovascular events rate, damage of target organs, atherosclerosis progression and new cases of diabetes mellitus. Losartan shows both high efficacy and low adverse event rate.

Efficacy of amlodipin in treatment of arterial hypertension.

The article summarizes the available data on amlodipin in hypertensive patients of high cardiovascular risk. The results of studies demonstrate strong and long-lasting antihypertensive effect of ramipril. Moreover, amlodipin treatment decreases cardiovascular events rate, damage of target organs and atherosclerosis progression. Amlodipin shows both high efficacy and good safety. All this properties make amlodipin extremely attractive for the everyday practice.

Ramipril therapy in the framework of evidence-based medicine

The article summarizes the available data on ramipril in hypertensive patients of high cardiovascular risk. The results of studies demonstrate strong and long-lasting antihypertensive effect of ramipril. Moreover, ramipril treatment decreases cardiovascular events rate, damage of target organs, atherosclerosis progression and new cases of diabetes mellitus. The treatment by ramipril represents vasculoprotective and renoprotective effects in diabetes patients. Possible antiarrhythmic activity of ramipril is of particular interest in atrial fi brillation. Ramipril shows both high effi cacy and low adverse event rate. All this properties make ramipril extremely attractive for the everyday practice.

A novel physiological property of snake bradykinin-potentiating peptides—Reversion of MK-801 inhibition of nicotinic acetylcholine receptors

The first naturally occurring angiotensin-converting enzyme (ACE) inhibitors described are pyroglutamyl proline-rich oligopeptides, found in the venom of the viper Bothrops jararaca, and named as bradykinin-potentiating peptides (BPPs). Biochemical and pharmacological properties of these peptides were essential for the development of Captopril, the first active site-directed inhibitor of ACE, currently used for the treatment of human hypertension. However, a number of data have suggested that the pharmacological activity of BPPs could not only be explained by their inhibitory action on enzymatic activity of somatic ACE. In fact, we showed recently that the strong and long-lasting anti-hypertensive effect of BPP-10c [<ENWPHPQIPP] is independent of somatic ACE inhibition. On the other hand, nicotinic acetylcholine receptors expressed in blood vessels have been related to blood pressure regulation. Therefore, we have studied the effects of BPP-10c on acetylcholine receptor function in the PC12 pheochromocytoma cell line, which following induction to neuronal differentiation expresses most of the nicotinic receptor subtypes. BPP-10c did not induce receptor-mediated ion flux, nor potentiated carbamoylcholine-provoked receptor activity as determined by whole-cell recording. This peptide, however, alleviated MK-801-induced inhibition of nicotinic acetylcholine receptor activity. Although more data are needed for understanding the mechanism of the BPP-10c effect on nicotinic receptor activity and its relationship with the anti-hypertensive activity, this work reveals possible therapeutic applications for BPP-10c in establishing normal acetylcholine receptor activity.