Displaying publications 1 - 20 of 71 in total

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  1. Manoharan S, Shuib AS, Abdullah N
    PMID: 28573254 DOI: 10.21010/ajtcam.v14i2.39
    BACKGROUND: The commercially available synthetic angiotensin-I-converting enzyme (ACE) inhibitors are known to exert negative side effects which have driven many research groups globally to discover the novel ACE inhibitors.

    METHOD: Literature search was performed within the PubMed, ScienceDirect.com and Google Scholar.

    RESULTS: The presence of proline at the C-terminal tripeptide of ACE inhibitor can competitively inhibit the ACE activity. The effects of other amino acids are less studied leading to difficulties in predicting potent peptide sequences. The broad specificity of the enzyme may be due to the dual active sites observed on the somatic ACE. The inhibitors may not necessarily competitively inhibit the enzyme which explains why some reported inhibitors do not have the common ACE inhibitor characteristics. Finally, the in vivo assay has to be carried out before the peptides as the antihypertensive agents can be claimed. The peptides must be absorbed into circulation without being degraded, which will affect their bioavailability and potency. Thus, peptides with strong in vitro IC50 values do not necessarily have the same effect in vivo and vice versa.

    CONCLUSION: The relationship between peptide amino acid sequence and inhibitory activity, in vivo studies of the active peptides and bioavailability must be studied before the peptides as antihypertensive agents can be claimed.

    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  2. Afzal S, Sattar MA, Johns EJ, Abdulla MH, Akhtar S, Hashmi F, et al.
    J Physiol Biochem, 2016 Dec;72(4):593-604.
    PMID: 27405250
    Adiponectin exerts vasodilatory effects. Irbesartan, an angiotensin receptor blocker, possesses partial peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist activity and increases circulating adiponectin. This study explored the effect of irbesartan alone and in combination with adiponectin on blood pressure, renal hemodynamic excretory function, and vasoactive responses to angiotensin II and adrenergic agonists in spontaneously hypertensive rat (SHR). Irbesartan was given orally (30 mg/kg/day) for 28 days and adiponectin intraperitoneally (2.5 μg/kg/day) for last 7 days. Groups of SHR received either irbesartan or adiponectin or in combination. A group of Wistar Kyoto rats (WKY) served as controls. Metabolic data and plasma samples were taken on days 0, 21, and 28. In acute studies, the renal vasoconstrictor actions of angiotensin II (ANGII), noradrenaline (NA), phenylephrine (PE), and methoxamine (ME) were determined. SHR control rats had a higher mean blood pressure than the WKY (132 ± 7 vs. 98 ± 2 mmHg), lower plasma and urinary adiponectin, creatinine clearance, urine flow rate and sodium excretion, and oxidative stress markers compared to WKY (all P 
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  3. Agarwal R, Agarwal P
    Ophthalmic Res, 2010;43(1):1-10.
    PMID: 19829006 DOI: 10.1159/000246571
    Glaucoma, a leading cause of irreversible blindness, is often associated with increased resistance to aqueous outflow in trabecular tissue. Increased outflow resistance has been attributed to increased extracellular matrix (ECM) deposition in trabecular tissue. A critical balance between the synthesis and breakdown of the components of extracellular tissue is important in keeping the intraocular pressure within the normal range. Multiple mechanisms have been shown to affect ECM turnover in trabecular tissue. In this review, we examine the related literature to understand the role of TGF-beta in ECM turnover, in the development and progression of glaucoma, and in possible therapeutic strategies that can be devised by targeting the TGF-beta signaling pathways.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  4. Choy CL, Sidi H, Koon CS, Ming OS, Mohamed IN, Guan NC, et al.
    J Sex Med, 2019 Jul;16(7):1029-1048.
    PMID: 31113742 DOI: 10.1016/j.jsxm.2019.04.007
    INTRODUCTION: Sexual dysfunction in hypertensive women is an often-neglected subject despite a reported prevalence of 42.1%. Although few reviews exist, a definitive relationship between hypertension and sexual dysfunction in women has not been clearly established.

    AIM: To review the existing literature to definitively examine sexual dysfunction in women with hypertension, in both treated and untreated subjects.

    METHODS: We performed a systematic search for published literature of 3 electronic databases (Scopus, EBSCOhost Medline Complete, and Cochrane Library) in August 2018. The search terms with relevant truncation and Boolean were developed according to a population exposure-comparator-outcome model combining pilot searches. The quality of included studies was assessed with the McMaster Critical Review Form for Quantitative Studies. Initial search, limited to the English language, included a total of 2,198 studies. 31 studies (18,260 subjects) met our inclusion criteria and were included in the review. Sexual dysfunction in these studies was measured using different tools. We extracted information of study setting, country, number of subjects, participants' age and blood pressure, comparators, and outcome. We ran a meta-analysis on the presence of sexual dysfunction as an outcome from the following comparisons: (i) hypertensive vs normotensive (ii) treated vs untreated hypertension, and (iii) exposure vs absence of specific class of anti-hypertensive drug.

    MAIN OUTCOME MEASURES: Women with sexual dysfunction and hypertension were included.

    RESULTS: We found significant sexual dysfunction in women with hypertension compared with the normotensive group (pooled odds ratio [OR] = 2.789, 95% CI = 1.452-5.357, P = .002). However, there was no statistical difference of sexual dysfunction in women with treated or untreated hypertension (OR = 1.229, 95% CI = 0.675-2.236, P = .5). Treatment with alpha-/beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium channel blockers, and diuretics resulted in no statistical difference in sexual dysfunction in hypertensive women.

    CLINICAL IMPLICATIONS: Because sexual dysfunction is prevalent in women with hypertension, it is imperative to address the underlying medical condition to manage this important clinical problem.

    STRENGTH & LIMITATIONS: Many studies had to be excluded from the meta-analysis, due to unavailability and incompleteness of data. Nevertheless, results of the review are useful to derive recommendations for alerting physicians of the need to routinely assess the sexual functioning of women with hypertension.

    CONCLUSION: We conclude that women with hypertension are at increased risk for sexual dysfunction, and our findings imply that evaluation for sexual dysfunction needs to be part of the clinical management guidelines for women with hypertension. Choy CL, Sidi H, Koon CS, et al. Systematic Review and Meta-Analysis for Sexual Dysfunction in Women With Hypertension. J Sex Med 2019;16:1029-1048.

    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  5. Ameer OZ, Salman IM, Siddiqui MJ, Yam MF, Sriramaneni RN, Mohamed AJ, et al.
    J Ethnopharmacol, 2010 Jan 8;127(1):19-25.
    PMID: 19808083 DOI: 10.1016/j.jep.2009.09.057
    The present study was aimed to investigate the pharmacological basis for the use of Loranthus ferrugineus in hypertension.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  6. Bello I, Usman NS, Mahmud R, Asmawi MZ
    J Ethnopharmacol, 2015 Dec 4;175:422-31.
    PMID: 26429073 DOI: 10.1016/j.jep.2015.09.031
    Alstonia scholaris has a long history of use in the Ayurveda traditional treatment of various ailments including hypertension. We have reported the blood pressure lowering activity of the extract of A. scholaris. The following research aim to delineate the pharmacological mechanism involve in the antihypertensive action.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  7. Ameer OZ, Salman IM, Siddiqui MJ, Yam MF, Sriramaneni RN, Sadikun A, et al.
    Am J Chin Med, 2009;37(5):991-1008.
    PMID: 19885958
    In the present study, L. ferrugineus methanol extract (LFME) was evaluated for its blood pressure lowering effect in anesthetized normotensive Sprague Dawley (SD) rats and its spasmogenic effect in isolated guinea pig ileum. The possible mechanism(s) of action were also investigated. LFME was obtained by Soxhlet extraction. The rats were fasted overnight and anesthetized with sodium pentobarbitone (60 mg/kg i.p.). LFME was administered in i.v. boluses in the concentrations of 25, 50, 100 and 200 mg/kg respectively, with concomitant monitoring of mean arterial pressure (MAP). It was found that LFME dose-dependently reduced MAP. An i.v. bolus injection of atropine significantly decreased the blood pressure lowering effect of LFME. Similarly, L-NAME (Nomega-nitro-L-arginine methyl ester) significantly lowered both the MAP and the action duration. Conversely, no significant change in MAP was seen following i.v. injections of neostigmine, hexamethonium, prazosin and propranolol. LFME also produced a dose-dependent contractile effect in guinea pig ileum. This contraction was significantly reduced in atropine pre-incubated tissue segments, yet it was significantly enhanced in the presence of neostigmine. No appreciable change in the ability of LFME to contract guinea pig ileum was seen in the presence of hexamethonium. Accordingly, it can be postulated that LFME possesses a marked hypotensive effect that can be attributed to stimulation of muscarinic receptors and/or stimulation of nitric oxide (NO) release. Moreover, LFME retains a considerable spasmogenic action due to its cholinergic properties. The hypotensive and spasmogenic effects of LFME justify its traditional uses.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  8. Lee SL, Lim WJ, Chai ST
    Med J Malaysia, 2020 09;75(5):591-593.
    PMID: 32918434
    A 67-year-old mental institute resident was treated for smear-positive pulmonary tuberculosis. His background history included chronic essential hypertension which was well-controlled with amlodipine 10mg daily. However, his blood pressure became suboptimal one week into antitubercular treatment, necessitating escalation of antihypertensive therapy up to six medications. Following completion of antitubercular treatment, his blood pressure improved markedly. The number of antihypertensives was able to be reduced to only two after a month. We postulate that rifampicin has attenuated the therapeutic effect of amlodipine via potent induction of hepatic CYP3A4 but the failure to control the blood pressure even with medications unrelated to cytochrome P450 pathways raises the spectre of an additional interaction.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  9. Abdullah HSTSH, Chia PW, Omar D, Chuah TS
    Sci Rep, 2021 07 09;11(1):14227.
    PMID: 34244589 DOI: 10.1038/s41598-021-93662-2
    Herbicide resistance is a worldwide problem in weed control. This prompts researchers to look for new modes of action to slow down the evolution of herbicide-resistant weeds. This research aims to determine the herbicidal action of thiazolo[3,2-a]pyrimidines derivatives, which are well known as antihypertensive drugs. The phytotoxic effects of ten compounds were investigated using leaf disc discoloration test and seed germination bioassay. At concentrations of 125 to 250 mg/L, the 5-(3-Fluoro-phenyl)-7-methyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylic acid ethyl ester (c) was highly active against Oldenlandia verticillata and Eleusine indica. At application rates of 1.25 to 2.5 kg ai/ha, formulated c demonstrated selective post-emergence and pre-emergence herbicidal activity against O. verticillata, E. indica and Cyperus iria. In the crop tolerance test, formulated c outperformed the commercial herbicide diuron, with aerobic Oryza sativa being the most tolerant, followed by Zea mays, and Brassica rapa. The addition of calcium chloride partially nullified compound c's inhibitory effects on weed shoot growth, indicating that it has potential as a calcium channel blocker. Compound c acted by triggering electrolyte leakage without affecting photosystem II. These findings imply that c could be explored further as a template for developing new herbicides with novel modes of action.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  10. Yeo JJP, Yeo LS, Tan SSN, Delailah DDRA, Lee SWH, Hu ATH, et al.
    Hypertens Res, 2024 Feb;47(2):352-357.
    PMID: 37673957 DOI: 10.1038/s41440-023-01418-4
    Resistant hypertension is a well-recognised clinical challenge. However, the definition and epidemiology of true resistant hypertension (RH) are less understood, especially in Asia. This cross-sectional study examined the prevalence of RH referred from primary care clinics based on various guidelines. RH was defined as blood pressure (BP) being above the threshold using ambulatory blood pressure monitoring despite adequate lifestyle measures and optimal treatment with ≥3 medications at maximally tolerated doses. Between one in four (n = 94, 24.0% using Malaysian guidelines) and up to two-thirds (n = 249, 63.7% using 2018 American guidelines) of adults referred for uncontrolled hypertension met the criteria of true RH. Of those with RH, a further one-quarter (n = 26, 26.6%) were deemed to have refractory hypertension (elevated BP despite treatment with at least 5 antihypertensive medications). Adults with RH were generally younger, more likely to be male, had a higher BMI and were more likely to have gout, CKD, and angina compared to those with controlled hypertension. The prevalence of RH amongst Asian adults with poor hypertension control is high. A concerted effort is needed to reduce the high burden of RH, especially among this population.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  11. Parker LM, Damanhuri HA, Fletcher SP, Goodchild AK
    Brain Res, 2015 Apr 16;1604:25-34.
    PMID: 25662772 DOI: 10.1016/j.brainres.2015.01.049
    Hypotensive drugs have been used to identify central neurons that mediate compensatory baroreceptor reflex responses. Such drugs also increase blood glucose. Our aim was to identify the neurochemical phenotypes of sympathetic preganglionic neurons (SPN) and adrenal chromaffin cells activated following hydralazine (HDZ; 10mg/kg) administration in rats, and utilize this and SPN target organ destination to ascribe their function as cardiovascular or glucose regulating. Blood glucose was measured and adrenal chromaffin cell activation was assessed using c-Fos immunoreactivity (-ir) and phosphorylation of tyrosine hydroxylase, respectively. The activation and neurochemical phenotype of SPN innervating the adrenal glands and celiac ganglia were determined using the retrograde tracer cholera toxin B subunit, in combination with in situ hybridization and immunohistochemistry. Blood glucose was elevated at multiple time points following HDZ administration but little evidence of chromaffin cell activation was seen suggesting non-adrenal mechanisms contribute to the sustained hyperglycemia. 16±0.1% of T4-T11 SPN contained c-Fos and of these: 24.3±1.4% projected to adrenal glands and 29±5.5% projected to celiac ganglia with the rest innervating other targets. 62.8±1.4% of SPN innervating adrenal glands were activated and 29.9±3.3% expressed PPE mRNA whereas 53.2±8.6% of SPN innervating celiac ganglia were activated and 31.2±8.8% expressed PPE mRNA. CART-ir SPN innervating each target were also activated and did not co-express PPE mRNA. Neurochemical coding reveals that HDZ administration activates both PPE+SPN, whose activity increase glucose mobilization causing hyperglycemia, as well as CART+SPN whose activity drive vasomotor responses mediated by baroreceptor unloading to raise vascular tone and heart rate.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  12. Lin DS, Wang TD, Buranakitjaroen P, Chen CH, Cheng HM, Chia YC, et al.
    J Clin Hypertens (Greenwich), 2021 03;23(3):556-567.
    PMID: 33305531 DOI: 10.1111/jch.14120
    Hypertension is a worldwide epidemic that continues to grow, with a subset of patients responding poorly to current treatment available. This is especially relevant in Asia, which constitutes 61% of the global population. Hypertension in Asia is a unique entity that is often salt-sensitive, nocturnal, and systolic predominant. Sacubitril/valsartan is a first-in-class angiotensin receptor neprilysin inhibitor that was first used in heart failure with reduced ejection fraction. Sacubitril inhibits neprilysin, a metallopeptidase that degrades natriuretic peptides (NPs). NPs exert sympatholytic, diuretic, natriuretic, vasodilatory, and insulin-sensitizing effects mostly via cyclic guanosine monophosphate (cGMP)-mediated pathways. As an antihypertensive agent, sacubitril/valsartan has outperformed angiotensin II receptor type 1 blockers (ARBs), with additional reductions of office systolic blood pressures ranging between 5 and 7 mmHg, in multiple studies in Asia and around the globe. The drug was well tolerated even in the elderly or those with chronic kidney disease. Its mechanisms of actions are particularly attractive for treatment of hypertension in Asia. Sacubitril/valsartan offers a novel, dual class, single-molecule property that may be considered as first-line antihypertensive therapy. Further investigations are needed to validate its safety for long-term use and to explore other potentials such as in the management of insulin resistance and obesity, which often coexist with hypertension in Asia.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  13. Kow CS, Zaidi STR, Hasan SS
    Am J Cardiovasc Drugs, 2020 Jun;20(3):217-221.
    PMID: 32281055 DOI: 10.1007/s40256-020-00406-0
    There is ongoing debate on the safety of renin-angiotensin system (RAS) inhibitors in COVID-19. Recently published studies highlight a potential relationship between cardiovascular disease (CVD) and COVID-19. This article aims to summarize the evidence on the use of RAS inhibitors in CVD patients with COVID-19, focusing on safety issues of the RAS inhibitors and their relationship with COVID-19.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  14. Chia YC, Devaraj NK, Ching SM, Ooi PB, Chew MT, Chew BN, et al.
    J Clin Hypertens (Greenwich), 2021 03;23(3):638-645.
    PMID: 33586334 DOI: 10.1111/jch.14212
    This study aimed to examine the relationship of adherence with blood pressure (BP) control and its associated factors in hypertensive patients. This cross-sectional nationwide BP screening study was conducted in Malaysia from May to October 2018. Participants with self-declared hypertension completed the Hill-Bone Compliance to High Blood Pressure Therapy Scale (Hill-Bone CHBPTS) which assesses three important domains of patient behavior to hypertension management namely medication taking, appointment keeping and reduced salt intake. Lower scores indicate better compliance while higher scores indicate otherwise. Participant's body mass index and seated BP were measured based on standard measurement protocol. Determinants of adherence to treatment were analyzed using multiple linear regression. Out of 5167 screened subjects, 1705 were known hypertensives. Of these, 927 (54.4%) answered the Hill-Bone CHBPTS and were entered into analysis. The mean age was 59.0 ± 13.2 years, 55.6% were female and 42.2% were Malays. The mean Hill-Bone CHBPTS score was 20.4 ± 4.4 (range 14-47), and 52.1% had good adherence. The mean systolic BP and diastolic BP were 136.4 ± 17.9 and 80.6 ± 11.6 mmHg, respectively. BP was controlled in 58.3% of those with good adherence compared to 50.2% in those with poor adherence (p = .014). Based on multiple linear regression analysis, female gender (β = -0.72, 95% confidence interval [CI] -1.30, -0.15, p = .014), older age (β = -0.05, 95% CI -0.07, -0.03, p 
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  15. Wang JG, Li Y, Chia YC, Cheng HM, Minh HV, Siddique S, et al.
    J Clin Hypertens (Greenwich), 2021 03;23(3):435-439.
    PMID: 33484617 DOI: 10.1111/jch.14194
    The prevalence of hypertension is high and still increasing in almost all communities regardless of high, middle, or low income. The control rate remains low in most countries. Telemedicine offers possibilities to improve blood pressure control. The past two decades witnessed the fast evolving telecommunication from telephone transmission to smart mobile phone technology for telemedicine. There is some evidence from randomized controlled trials that telemonitoring improves blood pressure control. However, it requires co-interventions. The emerging new technology may offer even more possibilities in telemonitoring and co-interventions, for instance, an interactive platform between patients and health professionals for the management of hypertension. Telemedicine might ultimately change the situation of the unsatisfactory management of hypertension in many communities. It helps fully utilize antihypertensive treatment, the most effective cardiovascular prevention, to achieve the goal of ending atherosclerosis and arteriosclerosis in humans.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  16. Razali N, Agarwal R, Agarwal P, Kapitonova MY, Kannan Kutty M, Smirnov A, et al.
    Eur J Pharmacol, 2015 Feb 15;749:73-80.
    PMID: 25481859 DOI: 10.1016/j.ejphar.2014.11.029
    Steroid-induced ocular hypertension (SIOH) is associated with topical and systemic use of steroids. However, SIOH-associated anterior and posterior segment morphological changes in rats have not been described widely. Here we describe the pattern of intraocular pressure (IOP) changes, quantitative assessment of trabecular meshwork (TM) and retinal morphological changes and changes in retinal redox status in response to chronic dexamethasone treatment in rats. We also evaluated the responsiveness of steroid-pretreated rat eyes to 5 different classes of antiglaucoma drugs that act by different mechanisms. Up to 80% of dexamethasone treated animals achieved significant and sustained IOP elevation. TM thickness was significantly increased and number of TM cells was significantly reduced in SIOH rats compared to the vehicle-treated rats. Quantitative assessment of retinal morphology showed significantly reduced thickness of ganglion cell layer (GCL) and inner retina (IR) in SIOH rats compared to vehicle-treated rats. Estimation of retinal antioxidants including catalase, superoxide dismutase and glutathione showed significantly increased retinal oxidative stress in SIOH animals. Furthermore, steroid-treated eyes showed significant IOP lowering in response to treatment with 5 different drug classes. This indicated the ability of SIOH eyes to respond to drugs acting by different mechanisms. In conclusion, SIOH was associated with significant morphological changes in TM and retina and retinal redox status. Additionally, SIOH eyes also showed IOP lowering in response to drugs that act by different mechanisms of action. Hence, SIOH rats appear to be an inexpensive and noninvasive model for studying the experimental antiglaucoma drugs for IOP lowering and neuroprotective effects.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  17. Siti HN, Kamisah Y, Mohamed S, Jaarin K
    Appl Physiol Nutr Metab, 2019 04;44(4):373-380.
    PMID: 30216735 DOI: 10.1139/apnm-2018-0175
    The prolonged intake of diet containing repeatedly heated vegetable oil can cause hypertension in the long run.
    In this study, the effects of citrus leaf extract (CLE) supplementation on vascular reactivity, plasma nitrite, and aortic structure in hypertensive rats were investigated by the consumption of repeatedly heated vegetable oil [corrected]. Male Sprague Dawley rats (n = 56) were divided into 7 groups corresponding to the respective diets. For 16 weeks, 1 group was given standard rat chow (control) while other groups were given diets containing 15% w/w of palm oil, fresh palm oil (FPO), palm oil heated 5 times (5HPO), and palm oil heated 10 times (10HPO), with or without the incorporation of 0.15% w/w CLE (FPO+CLE, 5HPO+CLE, or 10HPO+CLE). Plasma nitrite levels were measured before and at 16 weeks of treatment. After 16 weeks, the rats were sacrificed and aortae were harvested for measuring vascular reactivity and for microscopic study. CLE supplementation had significantly reduced the loss of plasma nitrite and attenuated the vasoconstriction response to phenylephrine in the 5HPO group but not in the 10HPO group. However, CLE had no significant effect on the vasorelaxation response to acetylcholine and sodium nitroprusside. The elastic lamellae of tunica media in 5HPO, 10HPO, and 10HPO+CLE groups appeared disorganised and disrupted. Obtained findings suggested that CLE was able to enhance nitric oxide bioavailability that might dampen the vasoconstriction effect of phenylephrine.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  18. Kamisah Y, Zuhair JSF, Juliana AH, Jaarin K
    Biomed Pharmacother, 2017 Dec;96:291-298.
    PMID: 28992471 DOI: 10.1016/j.biopha.2017.09.095
    Parkia speciosa Hassk is a plant found abundantly in Southeast Asia region. Its seeds with or without pods and roots have been used in traditional medicine in this region to treat hypertension. Therefore, we aimed to investigate the potential effect of the plant empty pod extract on hypertension development and changes in heart induced by N(G)-nitro-l-arginine methyl ester (l-NAME) administration in rats. Twenty-four male Sprague Dawley rats were divided into four groups. Groups 1 to 3 were given l-NAME (25mg/kg, intraperitoneally) for 8 weeks. Groups 2 and 3 were also given Parkia speciosa empty pods methanolic extract (800mg/kg, orally) and nicardipine (3mg/kg, orally), concurrently with l-NAME. The last group served as the control. l-NAME reduced plasma nitric oxide level and therefore, increased systolic blood pressure, angiotensin-converting enzyme and NADPH oxidase activities as well as lipid peroxidation in the heart. Parkia speciosa extract and nicardipine treatments had significantly prevented the elevations of blood pressure, angiotensin-converting enzyme, NADPH oxidase activities and lipid peroxidation in the heart induced by the l-NAME. Parkia speciosa extract but not nicardipine prevented the reduction in plasma nitric oxide level caused by l-NAME. In conclusion, Parkia speciosa empty pods methanolic extract has a potential to prevent the development of hypertension possibly by preventing the loss of plasma nitric oxide, as well as has cardioprotective effects by reducing angiotensin-converting enzyme activity and oxidative stress in the heart in rats administered l-NAME.
    Matched MeSH terms: Antihypertensive Agents/pharmacology
  19. Abdulla MH, Sattar MA, Abdullah NA, Khan MA, Abdallah HH, Johns EJ
    Eur J Pharmacol, 2009 Jun 10;612(1-3):69-74.
    PMID: 19356722 DOI: 10.1016/j.ejphar.2009.03.064
    This study set out to investigate the impact of chronic cumulative blockade of angiotensin II and adrenoceptors in WKY and SHR and to explore how the renovascular responses to adrenergic and angiotensin II receptor agonists may be interdependent. Rats were treated with either losartan, carvedilol or losartan+carvedilol for 7 days and on day eight, animals were pentobarbitone anaesthetized and prepared for renal haemodynamic study. Dose-response relationships were determined in terms of reduction/elevation in the magnitude of renal blood flow in response to intrarenal arterial injection of dopamine, phenylephrine and isoprenaline. Renal vascular responses were blunted in WKY and SHR treated with either losartan or carvedilol as compared to their untreated counterparts (P<0.05). In the combined treated rats, the vascular responses to isoprenaline and phenylephrine were restored to levels observed in the untreated rats, but the renal vasoconstrictor responses to dopamine decreased (P<0.05) in both WKY and SHR. There was a reduction of (P<0.05) in the magnitude of the isoprenaline induced renal vasodilation in all SHR as compared to WKY groups. The data obtained showed that the renal vascular action of dopamine, phenylephrine and isoprenaline depended on an intact renin-angiotensin system (RAS) in WKY and SHR. Treatment with losartan or carvedilol blunted the renal vasoconstrictor/vasodilator responses to sympathomimetics which was attenuated with the combined treatment. These observations using chronic blockade of adrenergic and angiotensin receptors demonstrated that there was a long standing interdependency between the RAS and sympathetic nervous system (SNS) in determining the responsiveness of the renal vasculature of normal and hypertensive rats.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
  20. Lazahari MI, Sattar MA, Abdullah NA, Khan MA, Johns EJ
    Methods Find Exp Clin Pharmacol, 2008 Apr;30(3):193-9.
    PMID: 18597003 DOI: 10.1358/mf.2008.30.3.1166221
    This study examined the sympathoinhibitory effects of clonidine and a novel clonidine analog, AL-12, in rat models of genetic hypertension and a combined state of genetic hypertension and diabetes. Rats in the treatment groups were given either clonidine or AL-12 while the respective control groups received either saline or Tween 80 for 6 days. Physiological data were collected during this period, which was followed by acute studies on day 7 when bolus administrations (i.v.) of graded doses of noradrenaline, phenylephrine and methoxamine were carried out. It was observed that in AL-12-treated nondiabetic spontaneously hypertensive rats (SHR), the pressure responses to all adrenergic agonists were greater (p < 0.05) in the treated group, while in the diabetic SHR rats a larger pressure response was observed only to noradrenaline (p < 0.05). In nondiabetic SHR rats treated with clonidine, a greater (p < 0.05) pressure response was observed only in the case of phenylephrine. In the diabetic SHR rats treated with clonidine, the pressure responses to the adrenergic agonists were similar (p > 0.05) in the treated and its control animals except that methoxamine caused a greater (p < 0.05) pressure response in the control group. The data obtained suggest that clonidine and AL-12 act possibly via vascular alpha1 and alpha2 adrenoceptors present at both pre- and postsynaptic locations.
    Matched MeSH terms: Antihypertensive Agents/pharmacology*
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