Displaying publications 41 - 58 of 58 in total

Abstract:
Sort:
  1. Fulltext The effect of sedation with a combination of butorphanol and midazolam on quantitative contrast-enhanced ultrasonography of duodenum in healthy dogs
    Nisa K, Lim SY, Osuga T, Yokoyama N, Tamura M, Nagata N, et al.
    J Vet Med Sci, 2018 Mar 24;80(3):453-459.
    PMID: 29398670 DOI: 10.1292/jvms.17-0525
    Quantitative contrast-enhanced ultrasonography (CEUS) enables non-invasive and objective evaluation of intestinal perfusion by quantifying the intensity of enhancement on the intestine after microbubble contrast administration. During CEUS scanning, sedation is sometimes necessary to maintain animal cooperation. Nevertheless, the effect of sedative administration on the canine intestinal CEUS is unknown. This study aimed to investigate the effect of sedation with a combination of butorphanol and midazolam on the duodenal CEUS-derived perfusion parameters of healthy dogs. For this purpose, duodenum was imaged following contrast administration (Sonazoid®, 0.01 ml/kg) in six healthy beagles before and after intravenous injection of a combination of butorphanol (0.2 mg/kg) and midazolam (0.1 mg/kg). Furthermore, hemodynamic parameters including blood pressure and heart rate were recorded during the procedure. Five CEUS derived perfusion parameters including time-to-peak (TTP), peak intensity (PI), area under the curve (AUC), wash-in and wash-out rates (WiR and WoR, respectively) before and after sedation were statistically compared. The result showed that no significant change was detected in any of perfusion parameters. Systolic and mean arterial pressures significantly reduced after sedative administration, but diastolic arterial pressure and heart rate did not significantly change. Moreover, no significant partial correlation was observed between perfusion parameters and hemodynamic parameters. Thus, we concluded that the combination did not cause significant influence in duodenal CEUS perfusion parameters and could be a good option for sedation prior to duodenal CEUS in debilitated dogs.
    Matched MeSH terms: Heart Rate/drug effects
  2. Standardized ethanol-water extract of Ficus deltoidea Angustifolia reduces blood pressure in spontaneously hypertensive rats
    Kamal MSA, Ismail NH, Satar NA, Azis NA, Radjeni Z, Mohammad Noor HS, et al.
    Clin Exp Hypertens, 2019;41(5):444-451.
    PMID: 30648895 DOI: 10.1080/10641963.2018.1506467
    Ficus deltoidea is used in Malay traditional medicine for the treatment of a number of disorders, including hypertension. There is, however, no scientific evidence on its anti-hypertensive effects. This study, therefore, investigated the effects of a standardized ethanolic-water extract of Ficus deltoidea Angustifolia (FD-A) on blood pressure (BP) in spontaneously hypertensive rats (SHR). Male SHR with systolic BP of >150 were divided into 4 groups (n = 8) and given either FD-A (800 or 1000 mg kg-1 day-1) or losartan (10 mg kg-1 day-1) or 0.5 ml of distilled water (control) daily for 28 days. BP, body weight, food and water intake, serum and urinary electrolytes, endothelin-1 (ET-1), total antioxidant capacity (TAC) and components of the renin-angiotensin-aldosterone system were measured. Data were analyzed using ANOVA with statistical significance set at p heart rate, and heart weight in FD-A and losartan-treated rats were significantly lower than those in the controls. Serum TAC and urinary calcium excretion were significantly higher, whereas serum ET-1 concentration was significantly lower in FD-A treated rats when compared to those in controls. No significant differences were found in the components of the renin-angiotensin-aldosterone system between controls and FD-A treated rats. In conclusion, FD-A when given daily at doses of either 800 or 1000 mg kg-1 day-1 body weight reduces BP in SHR. This effect does not seem to involve the renin-angiotensin-aldosterone-system but might involve some other mechanisms. Abbreviations: FD-A: Ficus deltoidea Angustifolia; ACE: Angiotensin-converting enzyme; SHR: Spontaneously hypertensive rats; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; AUC: Area under curve; RAAS: Renin Angiotensin Aldosterone System.
    Matched MeSH terms: Heart Rate/drug effects
  3. Salbutamol in premature labour--a preliminary report
    Ken DK, Ng KH
    Med J Malaysia, 1974 Mar;28(3):191-3.
    PMID: 4278259
    Matched MeSH terms: Heart Rate/drug effects
  4. Quercetin ameliorates oxidative stress, inflammation and apoptosis in the heart of streptozotocin-nicotinamide-induced adult male diabetic rats
    Roslan J, Giribabu N, Karim K, Salleh N
    Biomed Pharmacother, 2017 Feb;86:570-582.
    PMID: 28027533 DOI: 10.1016/j.biopha.2016.12.044
    Quercetin is known to possess beneficial effects in ameliorating diabetic complications, however the mechanisms underlying cardioprotective effect of this compound in diabetes is not fully revealed. In this study, quercetin effect on oxidative stress, inflammation and apoptosis in the heart in diabetes were investigated. Normal and streptozotocin-nicotinamide induced adult male diabetic rats received quercetin (10, 25 and 50mg/kg/bw) orally for 28days were anesthetized and hemodynamic parameters i.e. systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured. Blood was collected for analyses of fasting glucose (FBG), insulin and cardiac injury marker levels (troponin-C, CK-MB and LDH). Following sacrificed, heart was harvested and histopathological changes were observed. Heart was subjected for analyses of oxidative stress marker i.e. lipid peroxidation and activity and expression levels of anti-oxidative enzymes i.e. SOD, CAT and GPx. Levels of inflammation in the heart were determined by measuring nuclear factor (p65-NF-κB), tumor necrosis factor (TNF-α), interleukins (IL)-1β and IL-6 levels by using enzyme-linked immunoassay (ELISA). Distribution and expression levels of TNF-α and Ikk-β (inflammatory markers), caspase-3, caspase-9, Blc-2 and Bax (apoptosis markers) in the heart were identified by immunohistochemistry and Western blotting respectively.
    Matched MeSH terms: Heart Rate/drug effects
  5. Preclinical safety assessments of nano-sized constructs on cardiovascular system toxicity: A case for telemetry
    Cheah HY, Kiew LV, Lee HB, Japundžić-Žigon N, Vicent MJ, Hoe SZ, et al.
    J Appl Toxicol, 2017 Nov;37(11):1268-1285.
    PMID: 28165137 DOI: 10.1002/jat.3437
    While nano-sized construct (NSC) use in medicine has grown significantly in recent years, reported unwanted side effects have raised safety concerns. However, the toxicity of NSCs to the cardiovascular system (CVS) and the relative merits of the associated evaluation methods have not been thoroughly studied. This review discusses the toxicological profiles of selected NSCs and provides an overview of the assessment methods, including in silico, in vitro, ex vivo and in vivo models and how they are related to CVS toxicity. We conclude the review by outlining the merits of telemetry coupled with spectral analysis, baroreceptor reflex sensitivity analysis and echocardiography as an appropriate integrated strategy for the assessment of the acute and chronic impact of NSCs on the CVS. Copyright © 2017 John Wiley & Sons, Ltd.
    Matched MeSH terms: Heart Rate/drug effects
  6. Evaluation of a technique to measure heart rate variability in anaesthetised cats
    Khor KH, Shiels IA, Campbell FE, Greer RM, Rose A, Mills PC
    Vet J, 2014 Feb;199(2):229-35.
    PMID: 24321367 DOI: 10.1016/j.tvjl.2013.11.006
    Analysis of heart rate (HR) and heart rate variability (HRV) are powerful tools to investigate cardiac diseases, but current methods, including 24-h Holter monitoring, can be cumbersome and may be compromised by movement artefact. A commercially available data capture and analysis system was used in anaesthetised healthy cats to measure HR and HRV during pharmacological manipulation of HR. Seven healthy cats were subjected to a randomised crossover study design with a 7 day washout period between two treatment groups, placebo and atenolol (1mg/kg, IV), with the efficacy of atenolol to inhibit β1 adrenoreceptors challenged by epinephrine. Statistical significance for the epinephrine challenge was set at P<0.0027 (Holm-Bonferroni correction), whereas a level of significance of P<0.05 was set for other variables. Analysis of the continuous electrocardiography (ECG) recordings showed that epinephrine challenge increased HR in the placebo group (P=0.0003) but not in the atenolol group. The change in HR was greater in the placebo group than in the atenolol group (P=0.0004). Therefore, compared to cats pre-treated with placebo, pre-treatment with atenolol significantly antagonised the tachycardia while not significantly affecting HRV. The increased HR in the placebo group following epinephrine challenge was consistent with a shift of the sympathovagal balance towards a predominantly sympathetic tone. However, the small (but not significant at the critical value) decrease in the normalised high-frequency component (HFnorm) in both groups of cats suggested that epinephrine induced a parasympathetic withdrawal in addition to sympathetic enhancement (increased normalised low frequency component or LFnorm). In conclusion, this model is a highly sensitive and repeatable model to investigate HRV in anaesthetised cats that would be useful in the laboratory setting for short-term investigation of cardiovascular disease and subtle responses to pharmacological agents in this species.
    Matched MeSH terms: Heart Rate/drug effects*
  7. Time dependent effect of chronic embryonic exposure to ethanol on zebrafish: Morphology, biochemical and anxiety alterations
    Ramlan NF, Sata NSAM, Hassan SN, Bakar NA, Ahmad S, Zulkifli SZ, et al.
    Behav Brain Res, 2017 08 14;332:40-49.
    PMID: 28559182 DOI: 10.1016/j.bbr.2017.05.048
    Exposure to ethanol during critical period of development can cause severe impairments in the central nervous system (CNS). This study was conducted to assess the neurotoxic effects of chronic embryonic exposure to ethanol in the zebrafish, taking into consideration the time dependent effect. Two types of exposure regimen were applied in this study. Withdrawal exposure group received daily exposure starting from gastrulation until hatching, while continuous exposure group received daily exposure from gastrulation until behavioural assessment at 6dpf (days post fertilization). Chronic embryonic exposure to ethanol decreased spontaneous tail coiling at 24hpf (hour post fertilization), heart rate at 48hpf and increased mortality rate at 72hpf. The number of apoptotic cells in the embryos treated with ethanol was significantly increased as compared to the control. We also measured the morphological abnormalities and the most prominent effects can be observed in the treated embryos exposed to 1.50% and 2.00%. The treated embryos showed shorter body length, larger egg yolk, smaller eye diameter and heart edema as compared to the control. Larvae received 0.75% continuous ethanol exposure exhibited decreased swimming activity and increased anxiety related behavior, while withdrawal ethanol exposure showed increased swimming activity and decreased anxiety related behavior as compared to the respective control. Biochemical analysis exhibited that ethanol exposure for both exposure regimens altered proteins, lipids, carbohydrates and nucleic acids of the zebrafish larvae. Our results indicated that time dependent effect of ethanol exposure during development could target the biochemical processes thus leading to induction of apoptosis and neurobehavioral deficits in the zebrafish larvae. Thus it raised our concern about the safe limit of alcohol consumption for pregnant mother especially during critical periods of vulnerability for developing nervous system.
    Matched MeSH terms: Heart Rate/drug effects
  8. Fulltext A comparison of the maintenance and recovery charcateristic of sevoflurane-nitrous oxide against isoflurane-nitrous oxide anaesthesia
    Chiu CL, Chan YK, Ong GS, Delilkan AE
    Singapore Med J, 2000 Nov;41(11):530-3.
    PMID: 11284610
    To compare the maintenance and recovery characteristics of sevoflurane and isoflurane anaesthesia in Malaysian patients.
    Matched MeSH terms: Heart Rate/drug effects
  9. Dexmedetomidine and ketamine sedation for dental extraction in children with cyanotic heart disease
    Hasan MS, Chan L
    J Oral Maxillofac Surg, 2014 Oct;72(10):1920.e1-4.
    PMID: 24985961 DOI: 10.1016/j.joms.2014.03.032
    Treating children with cyanotic congenital heart disease poses many challenges to anesthesiologists because of the multiple problems associated with the condition. The anesthetic technique and drugs used perioperatively can affect a patient's physiologic status during surgery. The adherence to certain hemodynamic objectives and the avoidance of factors that could worsen the abnormal cardiopulmonary physiology cannot be overemphasized. In the present case series, we describe the use of a dexmedetomidine-ketamine combination for dental extraction in spontaneously breathing children with cyanotic congenital heart disease. The anesthetic concerns regarding airway management, the pharmacologic effects of drugs, and maintenance of adequate hemodynamic, blood gases, and acid-base status are discussed.
    Matched MeSH terms: Heart Rate/drug effects
  10. Hydrogen sulphide and tempol treatments improve the blood pressure and renal excretory responses in spontaneously hypertensive rats
    Ahmad FU, Sattar MA, Rathore HA, Tan YC, Akhtar S, Jin OH, et al.
    Ren Fail, 2014 May;36(4):598-605.
    PMID: 24502512 DOI: 10.3109/0886022X.2014.882218
    Oxidative stress and suppressed H2S production lead to increased renal vascular resistance, disturbed glomerular hemodynamics, and abnormal renal sodium and water handling, contribute to the pathogenesis and maintenance of essential hypertension in man and the spontaneously hypertensive rat. This study investigated the impact of H2S and tempol alone and in combination on blood pressure and renal hemodynamics and excretory functions in the SHR. Groups of WKY rats or SHR (n=6) were treated for 4 weeks either as controls or received NaHS (SHR+NaHS), tempol (SHR+Tempol), or NaHS plus tempol (SHR+NaHS +Tempol). Metabolic studies were performed on days 0, 14, and 28, thereafter animals were anaesthetized to measure renal hemodynamics and plasma oxidative and antioxidant markers. SHR control rats had higher mean arterial blood pressure (140.0 ± 2 vs. 100.0 ± 3 mmHg), lower plasma and urinary H2S, creatinine clearance, urine flow rate and urinary sodium excretion, and oxidative stress compared to WKY (all p<0.05). Treatment either with NaHS or with tempol alone decreased blood pressure and oxidative stress and improved renal hemodynamic and excretory function compared to untreated SHR. Combined NaHS and tempol therapy in SHRs caused larger decreases in blood pressure (∼20-22% vs. ∼11-15% and ∼10-14%), increases in creatinine clearance, urinary sodium excretion and fractional sodium excretion and up-regulated the antioxidant status compared to each agent alone (all p<0.05). These findings demonstrated that H2S and tempol together resulted in greater reductions in blood pressure and normalization of kidney function compared with either compound alone.
    Matched MeSH terms: Heart Rate/drug effects
  11. Efficacy and safety of dexmedetomidine versus morphine in post-operative cardiac surgery patients
    Abd Aziz N, Chue MC, Yong CY, Hassan Y, Awaisu A, Hassan J, et al.
    Int J Clin Pharm, 2011 Apr;33(2):150-4.
    PMID: 21744187 DOI: 10.1007/s11096-011-9480-7
    OBJECTIVE: To compare the efficacy of dexmedetomidine versus morphine as a sedative/analgesic among post-operative cardiac surgery patients.

    METHOD: A randomized controlled open-label study was performed at the cardiothoracic intensive care unit of Penang Hospital, Malaysia. A total of 28 patients who underwent cardiac surgeries were randomly assigned to receive either dexmedetomidine or morphine. Both groups were similar in terms of preoperative baseline characteristics. Efficacy measures included sedation scores and pain intensity and requirements for additional sedative/analgesic. Mean heart rate and arterial blood pressure were used as safety measures. Other measures were additional inotropes, extubation time and other concurrent medications.

    RESULTS: The mean dose of dexmedetomidine infused was 0.12 [SD 0.03] μg kg⁻¹ h⁻¹, while that of morphine was 13.2 [SD 5.84] μg kg⁻¹ h⁻¹. Dexmedetomidine group showed more benefits in sedation and pain levels, additional sedative/analgesic requirements, and extubation time. No significant differences between the two groups for the outcome measures, except heart rate, which was significantly lower in the dexmedetomidine group.

    CONCLUSION: This preliminary study suggests that dexmedetomidine was at least comparable to morphine in terms of efficacy and safety among cardiac surgery patients. Further studies with larger samples are recommended in order to determine the significant effects of the outcome measures.

    Matched MeSH terms: Heart Rate/drug effects
  12. The effect of losartan and carvedilol on vasopressor responses to adrenergic agonists and angiotensin II in the systemic circulation of Sprague Dawley rats
    Abdulla MH, Sattar MA, Abdullah NA, Khan MA, Anand Swarup KR, Johns EJ
    Auton Autacoid Pharmacol, 2011 Jan-Apr;31(1-2):13-20.
    PMID: 21166975 DOI: 10.1111/j.1474-8673.2010.00461.x
    1 Interaction between renin-angiotensin (RAS) and sympathetic nervous systems (SNS) was investigated by examining the effect of cumulative blockade of angiotensin II (Ang II) and adrenergic receptors in normal Sprague Dawley rats. 2 Rats were treated with losartan (10 mg/kg), carvedilol (5 mg/kg), or losartan plus carvedilol (10+5 mg/kg) orally for 7 days. On day 8, the animals were anaesthetized with pentobarbitone and prepared for systemic haemodynamic study. Dose-response relationships for the elevation of mean arterial pressure or change in heart rate (HR) in response to intravenous injections of noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II were determined. 3 Losartan or the combination of losartan with carvedilol blunted vasopressor responses to ME and Ang II. Dose-response relationships for agonist action on HR were significantly inhibited by all treatments except for the combination of losartan and carvedilol on the decrease in HR induced by PE. Carvedilol decreased vasopressor responses to NA, PE and Ang II, and HR responses to NA, ME and Ang II. Combination treatment produced similar effects to losartan on the vasopressor and HR responses but had a greater effect on vasopressor responses to ME and Ang II, and on HR responses to NA and Ang II than carvedilol alone. 4 It is concluded that peripheral vasoconstriction induced by Ang II is partly mediated by adrenergic action and that the vasopressor responses to adrenergic agonists depend on an intact RAS. These observations suggest an interactive relationship between RAS and SNS in determining systemic haemodynamic responses in 'normal' rats.
    Matched MeSH terms: Heart Rate/drug effects
  13. Real-life safety and effectiveness of amlodipine/valsartan combination in the treatment of hypertension
    Chazova IE, Dongre N, Vigdorchik AV
    Adv Ther, 2011 Feb;28(2):134-49.
    PMID: 21240661 DOI: 10.1007/s12325-010-0099-1
    The aim of our study was to evaluate the safety and effectiveness of the free combination of amlodipine/valsartan in patients with arterial hypertension in a real-life setting.
    Matched MeSH terms: Heart Rate/drug effects*
  14. Chronic treatment with losartan and carvedilol differentially modulates renal vascular responses to sympathomimetics compared to treatment with individual agents in normal Wistar Kyoto and spontaneously hypertensive rats
    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: Heart Rate/drug effects
  15. Fulltext Super, red palm and palm oleins improve the blood pressure, heart size, aortic media thickness and lipid profile in spontaneously hypertensive rats
    Boon CM, Ng MH, Choo YM, Mok SL
    PLoS One, 2013;8(2):e55908.
    PMID: 23409085 DOI: 10.1371/journal.pone.0055908
    Oleic acid has been shown to lower high blood pressure and provide cardiovascular protection. Curiosity arises as to whether super olein (SO), red palm olein (RPO) and palm olein (PO), which have high oleic acid content, are able to prevent the development of hypertension.
    Matched MeSH terms: Heart Rate/drug effects
  16. Interaction between irbesartan, peroxisome proliferator-activated receptor (PPAR-γ), and adiponectin in the regulation of blood pressure and renal function in spontaneously hypertensive rats
    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 drug treatments and to a greater extent by combined treatment. Responses to intrarenal administration of NA, PE, ME, and ANGII were larger in SHR (P 
    Matched MeSH terms: Heart Rate/drug effects
  17. An investigation of the antiplatelet effects of succinobucol (AGI-1067)
    Houston SA, Ugusman A, Gnanadesikan S, Kennedy S
    Platelets, 2017 May;28(3):295-300.
    PMID: 27681689 DOI: 10.1080/09537104.2016.1218456
    Succinobucol is a phenolic antioxidant with anti-inflammatory and antiplatelet effects. Given the importance of oxidant stress in modulating platelet-platelet and platelet-vessel wall interactions, the aim of this study was to establish if antioxidant activity was responsible for the antiplatelet activity of succinobucol. Platelet aggregation in response to collagen and adenosine diphosphate (ADP) was studied in rabbit whole blood and platelet-rich plasma using impedance aggregometry. The effect of oxidant stress on aggregation, platelet lipid peroxides, and vascular tone was studied by incubating platelets, washed platelets or preconstricted rabbit iliac artery rings respectively with a combination of xanthine and xanthine oxidase (X/XO). To study the effect of succinobucol in vivo, anaesthetized rats were injected with up to 150 mg/kg succinobucol and aggregation measured in blood removed 15 mins later. Succinobucol (10-5-10-4M) significantly attenuated platelet aggregation to collagen and ADP in whole blood and platelet-rich plasma. X/XO significantly increased aggregation to collagen and platelet lipid peroxides and this was reversed by succinobucol. Addition of X/XO to denuded rabbit iliac arteries caused a dose-dependent relaxation which was significantly inhibited by succinobucol. In vivo administration up to 150 mg/kg had no effect on heart rate or mean arterial blood pressure but significantly inhibited platelet aggregation to collagen ex vivo. In conclusion, succinobucol displays anti-platelet activity in rabbit and rat blood and reverses the increase in platelet aggregation in response to oxidant stress.
    Matched MeSH terms: Heart Rate/drug effects
  18. Blood pressure lowering effect and vascular activity of Phyllanthus niruri extract: The role of NO/cGMP signaling pathway and β-adrenoceptor mediated relaxation of isolated aortic rings
    Bello I, Usman NS, Dewa A, Abubakar K, Aminu N, Asmawi MZ, et al.
    J Ethnopharmacol, 2020 Mar 25;250:112461.
    PMID: 31830549 DOI: 10.1016/j.jep.2019.112461
    ETHNOPHARMACOLOGICAL RELEVANCE: Phyllanthus niruri have a long history of use in the traditional treatment of various ailments including hypertension. Literature reports have indicated that it is a potent antihypertensive herbal medication used traditionally.

    AIM OF THE STUDY: This study was carried out to investigate the antihypertensive and vasodilatory activity of four solvents extracts of P. niruri namely; petroleum ether (PEPN), chloroform (CLPN), methanol (MEPN) and water (WEPN), with the aim of elucidating the mechanism of action and identifying the phytochemical constituents.

    MATERIALS AND METHODS: Male Spontaneous Hypertensive Rats (SHRs) were given oral gavage of P. niruri extract daily for two weeks and the blood pressure was recorded in vivo. We also determine the vasodilation effect of the extracts on rings of isolated thoracic aorta pre-contracted with phenylephrine (PE, 1 μM). Endothelium-intact or endothelium-denuded aorta rings were pre-incubated with various antagonists like 1H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, 10 μM) and Methylene blue (MB 10 μM), sGC inhibitors; Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME, 10 μM) a nitric oxide synthase (NOS) inhibitor; atropine (10 μM), a cholinergic receptor blocker; indomethacin (10 μM), a cyclooxygenase inhibitor and various K+ channel blockers such as glibenclamide (10 μM) and tetraethyl ammonium (TEA 10 μM) for mechanism study.

    RESULTS: SHRs receiving P. niruri extracts showed a significant decrease in their blood pressure (BP) when compared to the baseline value, with PEPN being more potent. The extracts (0.125-4 mg/mL) also induced vasorelaxation on endothelium-intact aorta rings. PEPN elicited the most potent maximum relaxation effect (Rmax). Mechanism assessment of PEPN showed that its relaxation effect is significantly suppressed in endothelium-denuded aorta rings. Pre-incubation of aorta rings with atropine, L-NAME, ODQ, indomethacin, and propranolol also significantly attenuated its relaxation effect. Conversely, incubation with TEA and glibenclamide did not show a significant effect on PEPN-induced relaxation.

    CONCLUSION: This study indicates that the antihypertensive activity of P. niruri extract is mediated by vasoactive phytoconstituents that dilate the arterial wall via endothelium-dependent pathways and β-adrenoceptor activity which, in turn, cause vasorelaxation and reduce blood pressure.

    Matched MeSH terms: Heart Rate/drug effects
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links