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  1. Fulltext Role of excitatory amino acid input in rostral ventrolateral medulla neurons in rats with obesity-induced hypertension
    Suhaimi FW, Yusoff NH, Dewa A, Yusof AP
    Acta Neurol Belg, 2010 Mar;110(1):57-64.
    PMID: 20514927
    Obesity is intimately associated with hypertension; increases in blood pressure are closely related to the magnitude of weight gain. The present study aims to determine whether the excitatory amino acid input to rostral ventrolateral medulla (RVLM) contributes to elevated blood pressure in rats with diet-induced obesity. Male Sprague-Dawley rats weighing 280 to 300 grams were fed with a low-fat diet (10% kcal from fat) or moderately high-fat diet (32% kcal from fat) for 16 weeks. At week 16, rats on the moderate high-fat diet were segregated into obesity-prone and obesity-resistant rats based on body weight distribution. Baseline mean arterial pressure (MAP) was significantly higher in obesity-prone rats as compared to obesity-resistant and rats on a low-fat diet. Bilateral injection of kynurenic acid (KYN) (40 nM) into the RVLM of the obesity-prone rats reduced MAP to levels significantly different from those observed in rats on a low-fat diet and obesity-resistant rats (no change in MAP). At a lower concentration (4 nM), KYN injection did not produce any change in MAP in any group. The results obtained suggest that excitatory amino acid input to the RVLM does contribute to the development of hypertension in rats with diet-induced obesity.
    Matched MeSH terms: Blood Pressure/drug effects
  2. Blunted endogenous GABA-mediated inhibition in the hypothalamic paraventricular nucleus of rats with streptozotocin-induced diabetes
    Hassan Z, Sattar MZ, Suhaimi FW, Yusoff NH, Abdulla MH, Yusof AP, et al.
    Acta Neurol Belg, 2013 Sep;113(3):319-25.
    PMID: 23242937 DOI: 10.1007/s13760-012-0165-3
    The hypothalamic paraventricular nucleus (PVN) is involved in the regulation of sympathetic outflow and particularly affects the heart. This study sets out to determine the role of GABA of the paraventricular nucleus (PVN) in cardiovascular regulation in streptozotocin-induced diabetic rats. Pharmacological stimulation of glutamatergic receptors with DL-Homocysteic acid (200 mM in 100 nL) in the PVN region showed a significant depression in both mean arterial pressure (MAP) and heart rate (HR) of diabetic rats (Diabetic vs. non-diabetic: MAP 15.0 ± 1.5 vs. 35.8 ± 2.8 mmHg; HR 3.0 ± 2.0 vs. 30.0 ± 6.0 bpm, P < 0.05). Microinjection of bicuculline methiodide (1 mM in 100 nL), a GABAA receptor antagonist, produced an increase in baseline MAP and HR in both non-diabetic and diabetic rats. In the diabetic rats, bicuculline injection into the PVN reduced the pressor and HR responses (Diabetic vs. non-diabetic: MAP 6.2 ± 0.8 vs. 25.1 ± 2.2 mmHg; HR 1.8 ± 1.1 vs. 25.4 ± 6.2 bpm, P < 0.05). A microinjection of muscimol (2 mM in 100 nL), which is a GABAA receptor agonist, in the PVN elicited decreases in MAP and HR in both groups. The diabetic group showed a significantly blunted reduction in HR, but not MAP (Diabetic vs. non-diabetic: MAP -15.7 ± 4.0 vs. -25.0 ± 3.8 mmHg; HR -5.2 ± 2.1 vs. -39.1 ± 7.9 bpm). The blunted vasopressor and tachycardic responses to bicuculline microinjection in the diabetic rats are likely to result from decreased GABAergic inputs, attenuated release of endogenous GABA or alterations in GABAA receptors within the PVN.
    Matched MeSH terms: Blood Pressure/drug effects
  3. Contribution of kinin system to the antihypertensive action of angiotensin converting enzyme inhibitors
    Sharma JN
    Adv Exp Med Biol, 1989;247A:197-205.
    PMID: 2690588
    Matched MeSH terms: Blood Pressure/drug effects*
  4. Metabolomics, Lipidomics and Pharmacometabolomics of Human Hypertension
    Au A, Cheng KK, Wei LK
    Adv Exp Med Biol, 2017;956:599-613.
    PMID: 27722964 DOI: 10.1007/5584_2016_79
    Hypertension is a common but complex human disease, which can lead to a heart attack, stroke, kidney disease or other complications. Since the pathogenesis of hypertension is heterogeneous and multifactorial, it is crucial to establish a comprehensive metabolomic approach to elucidate the molecular mechanism of hypertension. Although there have been limited metabolomic, lipidomic and pharmacometabolomic studies investigating this disease to date, metabolomic studies on hypertension have provided greater insights into the identification of disease-specific biomarkers, predicting treatment outcome and monitor drug safety and efficacy. Therefore, we discuss recent updates on the applications of metabolomics technology in human hypertension with a focus on metabolic biomarker discovery.
    Matched MeSH terms: Blood Pressure/drug effects*
  5. 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: Blood Pressure/drug effects*
  6. Influence of a kinin antagonist on acute hypotensive responses induced by bradykinin and captopril in spontaneously hypertensive rats
    Sharma JN, Stewart JM, Mohsin SS, Katori M, Vavrek R
    Agents Actions Suppl., 1992;38 ( Pt 3):258-69.
    PMID: 1334354
    We have evaluated the effects of a B2 receptor antagonist (B5630) of kinins on BK and captopril-induced acute hypotensive responses in anaesthetized SHR. Intravenous treatment of BK (1.0 microgram) and captopril (0.3 mg/kg) caused significant (p < 0.05) fall in the SBP and DBP. Whereas BK caused greater fall in the SBP (p < 0.05), DBP (p < 0.01) and duration of hypotension (p < 0.05) when administered after captopril (Fig 1 and 2). All the hypotensive effects of BK and captopril were significantly antagonised (p < 0.05) in the presence of B5630 (2.0 mg/kg). Further, the duration of hypotensive responses of BK and captopril were blocked (p < 0.05) by B5630. The agonists and BK-antagonist did not cause significant (p > 0.05) alterations in HR during the entire investigation. These findings provide evidence to support the suggestion that B2 receptor might be involved in the regulation of the hypotensive actions of BK and captopril. Kinins should also have valuable functions in the antihypertensive property of captopril-like drugs.
    Matched MeSH terms: Blood Pressure/drug effects*
  7. The effect of prophylactic metaraminol on systemic hypotension caused by induction of anaesthesia with propofol in patients over 55 years old
    Chiu CL, Tew GP, Wang CY
    Anaesthesia, 2001 Sep;56(9):893-7.
    PMID: 11531679
    We conducted a double-blind, randomised, placebo-controlled study evaluating the efficacy of prophylactic metaraminol for preventing propofol-induced hypotension. Thirty patients aged 55-75 years undergoing general anaesthesia were randomly allocated to receive either metaraminol 0.5 mg or saline before administration of fentanyl 1 microg.kg(-1) and propofol 2 mg.kg(-1). Induction of anaesthesia was associated with a decrease in mean and systolic arterial pressure in both groups (p = 0.0001). However, there was no significant difference between the two groups. These results show that prophylactic use of metaraminol 0.5 mg does not prevent the decrease in blood pressure following fentanyl and propofol induction in older patients.
    Matched MeSH terms: Blood Pressure/drug effects
  8. The effect of mivacurium pretreatment on intra-ocular pressure changes induced by suxamethonium
    Chiu CL, Lang CC, Wong PK, Delilkan AE, Wang CY
    Anaesthesia, 1998 May;53(5):501-5.
    PMID: 9659028
    Forty patients without eye disease, undergoing elective nonophthalmic surgery, were studied in a double-blind, randomised, placebo-controlled study evaluating the efficacy of mivacurium pretreatment in attenuating the rise in intra-ocular pressure in response to suxamethonium administration, laryngoscopy and intubation. The patients were randomly allocated to receive either mivacurium 0.02 mg.kg-1 or normal saline as pretreatment 3 min before a rapid sequence induction technique using alfentanil, propofol and suxamethonium. Suxamethonium induced a significant increase in intra-ocular pressure in the control group but not in the mivacurium pretreatment group (mean (SEM) increase = 3.5 (1.2) mmHg vs. 0.4 (0.8) mmHg, p < 0.05). There was a decrease in intra-ocular pressure in both groups after laryngoscopy and intubation with no significant difference between the two groups. These results show that mivacurium pretreatment is effective in preventing the increase in intra-ocular pressure after suxamethonium administration.
    Matched MeSH terms: Blood Pressure/drug effects
  9. Comparison between the effects of propofol and etomidate on motor and electroencephalogram seizure duration during electroconvulsive therapy
    Tan HL, Lee CY
    Anaesth Intensive Care, 2009 Sep;37(5):807-14.
    PMID: 19775046
    An ideal anaesthetic for electroconvulsive therapy (ECT) should have rapid onset and offset with no effect on seizure duration, and provide cardiovascular stability during the procedure. Propofol is commonly used, even though it has been shown to shorten seizure duration which might affect the efficacy of ECT Etomidate has been advocated as an alternative. This prospective, randomised, single-blind, crossover study was conducted to compare the effects of etomidate (Etomidate-Lipuro, B. Braun Ltd, Melsungen, Germany) and propofol (Diprivan, AstraZeneca, UK) on seizure duration as well as haemodynamic parameters in patients undergoing ECT Twenty patients aged between 18 and 70 years were recruited. Group I received etomidate 0.3 mg/kg for the first course of ECT (Group IA) and propofol 1.5 mg/kg for the second ECT (Group IB), while Group II received propofol for the first ECT (Group IIA) and etomidate for the second ECT (Group IIB). There was a washout period of two to three days in between procedures. Parameters recorded included motor seizure duration, electroencephalogram seizure duration, blood pressure and heart rate. Analysis demonstrated neither period effect nor treatment period interaction. Etomidate was associated with a significantly longer motor and electroencephalogram seizure duration compared with propofol (P < 0.01). Neither drug demonstrated consistent effects in suppressing the rise in heart rate or blood pressure during ECT Myoclonus and pain on injection were the most common adverse effects in etomidate group and propofol group respectively. Etomidate is a useful anaesthetic agent for ECT and should be considered in patients with inadequate seizure duration with propofol.
    Matched MeSH terms: Blood Pressure/drug effects
  10. Randomized double-blind comparison of ketamine-propofol, fentanyl-propofol and propofol-saline on haemodynamics and laryngeal mask airway insertion conditions
    Goh PK, Chiu CL, Wang CY, Chan YK, Loo PL
    Anaesth Intensive Care, 2005 Apr;33(2):223-8.
    PMID: 15960405
    The aim of this prospective, double-blind, randomized, placebo-controlled clinical trial was to investigate whether the administration of ketamine before induction with propofol improves its associated haemodynamic profile and laryngeal mask airway (LMA) insertion conditions. Ninety adult patients were randomly allocated to receive either ketamine 0.5 mg x kg(-1) (n = 30), fentanyl 1 microg x kg(-1) (n = 30) or normal saline (n = 30), before induction of anaesthesia with propofol 2.5 mg x kg(-1). Insertion of the LMA was performed 60s after injection of propofol. Arterial blood pressure and heart rate were measured before induction (baseline), immediately after induction, immediately before LMA insertion, immediately after LMA insertion and every minute for three minutes after LMA insertion. Following LMA insertion, the following six subjective endpoints were graded by a blinded anaesthestist using ordinal scales graded 1 to 3: mouth opening, gagging, swallowing, movement, laryngospasm and ease of insertion. Systolic blood pressure was significantly higher following ketamine than either fentanyl (P = 0.010) or saline (P = 0.0001). The median (interquartile range) summed score describing the overall insertion conditions were similar in the ketamine [median 7.0, interquartile range (6.0-8.0)] and fentanyl groups [median 7.0, interquartile range (6.0-8.0)]. Both appeared significantly better than the saline group [median 8.0, interquartile range (6.75-9.25); P = 0.024]. The incidence of prolonged apnoea (> 120s) was higher in the fentanyl group [23.1% (7/30)] compared with the ketamine [6.3% (2/30)] and saline groups [3.3% (1/30)]. We conclude that the addition of ketamine 0.5 mg x kg(-1) improves haemodynamics when compared to fentanyl 1 microg x kg(-1), with less prolonged apnoea, and is associated with better LMA insertion conditions than placebo (saline).
    Matched MeSH terms: Blood Pressure/drug effects*
  11. Effects of citrus leaf extract on aortic vascular reactivity in hypertensive rats fed repeatedly heated vegetable oil
    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: Blood Pressure/drug effects*
  12. Heated palm oil causes rise in blood pressure and cardiac changes in heart muscle in experimental rats
    Leong XF, Aishah A, Nor Aini U, Das S, Jaarin K
    Arch Med Res, 2008 Aug;39(6):567-72.
    PMID: 18662587 DOI: 10.1016/j.arcmed.2008.04.009
    Palm oil used worldwide contains considerable amounts of antioxidants, namely, vitamin E and carotenes. The purpose of the study was to observe the effect of heated palm oil on blood pressure and observe the cardiac histological changes in rats.
    Matched MeSH terms: Blood Pressure/drug effects*
  13. RAS Genetic Variants in Interaction with ACE Inhibitors Drugs Influences Essential Hypertension Control
    Heidari F, Vasudevan R, Mohd Ali SZ, Ismail P, Arkani M
    Arch Med Res, 2017 Jan;48(1):88-95.
    PMID: 28577874 DOI: 10.1016/j.arcmed.2017.03.003
    BACKGROUNDS AND AIMS: Essential Hypertension (EH) is a common disorder associated with increased cardiovascular morbidity and mortality in Malaysia. To investigate how genetic polymorphisms of the renin-angiotensin-aldosterone system (RAS) influence EH control with angiotensin-converting enzyme inhibitor drugs (ACEI).

    METHODS: A case-control, cross-sectional population-based nested study (n = 142) included hypertensive subjects treated with ACEI drugs, either lisinopril or enalapril (20 mg, once daily) as monotherapy for 24 weeks. In total seven possible polymorphisms of RAS genes were genotyped. The association between those polymorphisms and the changes in blood pressure were observed in the 24 week treatment.

    RESULTS: Statistically significant associations of I, G, T, M and G alleles of ACE (I/D, G2350A), AGT (M235T, T175M and G-6A) respectively were observed in essential hypertensive subjects. The decrease in systolic blood pressure and diastolic blood pressure after 24 weeks of treatment of the patients carrying II, GG, and TT genotypes were greater than the groups carrying DD, AA, MM, MM and GG of I/D, G2350A, M235T, T174M and G-6A genotypes respectively. In contrast, No significant difference was observed between renin gene polymorphisms (Bg/I and MboI) and hypertensives.

    CONCLUSIONS: Although this study shows a possible association of polymorphisms of RAS genes with the risk of non-control of HT in ACEI-treated patients and indicates the importance of all this system's components in regulating HT, it needs to be replicated in other data sources.

    Matched MeSH terms: Blood Pressure/drug effects
  14. Arterial compliance and vitamin E blood levels with a self emulsifying preparation of tocotrienol rich vitamin E
    Rasool AH, Rahman AR, Yuen KH, Wong AR
    Arch Pharm Res, 2008 Sep;31(9):1212-7.
    PMID: 18806966 DOI: 10.1007/s12272-001-1291-5
    The tocotrienol vitamin E has potent antioxidant property, however absorption is low due to high lipid solubility. A self emulsifying preparation of tocotrienol rich vitamin E (SF-TRE) had been reported to increase their bioavailability. This randomized, placebo controlled, blinded end point clinical study aimed to determine the effects of 50, 100 and 200 mg daily of SF-TRE and placebo for two months on arterial compliance and vitamin E blood levels. Assessment of arterial compliance by carotid femoral pulse wave velocity (PWV) and augmentation index (AI), plasma vitamin E, serum total cholesterol and low density lipoprotein cholesterol were taken before and after 2 months' treatment in 36 healthy males. Un-supplemented tocotrienol levels were low, after treatment, all SF-TRE treated groups had significantly higher plasma alpha, delta and delta tocotrienol concentrations compared to placebo. Augmentation index change from baseline to end of treatment for groups placebo, 50, 100, and 200 mg were 2.22+/-1.54, -6.59+/-2.84, -8.72+/-3.77, and -6.27+/-2.67% respectively (p=0.049, 0.049, and 0.047 respectively). Groups 100 and 200 mg showed significant improvement after treatment with pulse wave velocity reductions of 0.77 m/s and 0.65 m/s respectively (p=0.007 and p=0.002). There was no effect of SF-TRE on serum lipids. We conclude that there was a trend towards improvement in arterial compliance with 2 months' of SF-TRE.
    Matched MeSH terms: Blood Pressure/drug effects
  15. Fulltext Does a single cup of caffeinated drink significantly increase blood pressure in young adults? A randomised controlled trial
    Teng CL, Lim WY, Chua CZ, Teo RS, Lin KT, Yeo JC
    Aust Fam Physician, 2016;45(1):65-8.
    PMID: 27051992
    BACKGROUD: Previous studies have shown that the blood pressure elevating effect of acute caffeine consumption was variable because of the heterogeneity of study participants, dosage of caffeine and study designs.
    OBJECTIVE: This research aimed to examine the effect of a single cup of coffee on the blood pressure of young adults.
    METHODS: Normotensive adults were randomised to receive either a cup of caffeinated drink (intervention group) or a cup of decaffeinated drink (control group). The main outcome measure was mean change in systolic blood pressure (SBP) and diastolic blood pressure (DBP) between intervention and control groups.
    RESULTS: Enrolled participants (n = 104) were randomly assigned to the intervention group (n = 53) or the control group (n = 51). The mean differences in SBP and DBP of the two groups were +2.77 mmHg (P = 0.05) and +2.11 mmHg (P = 0.64), respectively. Therefore, the rise in both SBP and DBP after caffeine consumption was not statistically significant.
    DISCUSSION: Our study confirmed that drinking a single cup of coffee (containing 80 mg of caffeine) does not have a significant impact on the blood pressure of healthy normotensive young adults one hour after the drink.
    Matched MeSH terms: Blood Pressure/drug effects*
  16. 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: Blood Pressure/drug effects*
  17. Interaction between renin-angiotensin and sympathetic nervous systems in a rat model of pressure overload cardiac hypertrophy
    Rathore HA, Munavvar AS, Abdullah NA, Khan AH, Fathihah B, NurJannah MH, et al.
    Auton Autacoid Pharmacol, 2009 Oct;29(4):171-80.
    PMID: 19740088 DOI: 10.1111/j.1474-8665.2009.00445.x
    1 A raised cardiac workload activates neurohormones which will increase muscle mass and shift contractility to the right along the Frank-Starling curve. 2 This study examined the interaction between the SNS and RAS in contributing to vascular responsiveness following the development of cardiac hypertrophy due to aortic banding. 3 Sprague Dawley rats (180-200 g) were assigned to one of six groups; Normal, Sham-operated, Aortic Banded (AB), Aortic Banded treated with losartan (ABLOS), Aortic Banded treated with 6-hydroxydopamine (ABSYMP) and Aortic banded treated with both losartan and 6-hydroxydopamine (ABSYMPLOS). A constricting band was placed around the supra renal aorta on day zero with drug treatment from day 37 to day 44. Vasopressor responses to noradrenaline, phenylephrine, methoxamine and angiotensin II were measured on day 45. 4 The magnitudes of the MAP responses to all vasoactive agents, expressed as percentage changes, were similar in Normal and Sham groups, but reduced in the AB group. ABLOS group showed attenuated response to ANGII whereas all responses were enhanced in the ABSYM group. 5 A positive interaction between the two systems was observed with alpha(1A)-adrenoceptors identified as a major component of SNS and AT(1) receptors of RAS to induce vasopressor effects.
    Matched MeSH terms: Blood Pressure/drug effects
  18. Influence of high dietary sodium intake on the functional subtypes of alpha-adrenoceptors in the renal cortical vasculature of Wistar-Kyoto rats
    Kazi RN, Munavvar AS, Abdullah NA, Khan AH, Johns EJ
    Auton Autacoid Pharmacol, 2009 Jan;29(1-2):25-31.
    PMID: 19302553 DOI: 10.1111/j.1474-8673.2009.00428.x
    1 Increased renal vascular resistance is one renal functional abnormality that contributes to hypertension, and alpha(1)-adrenoceptors play a pivotal role in modulating this renal vascular resistance. This study investigates the functional contribution of alpha(1)-adrenoceptor subtypes in the renal cortical vasculature of Wistar-Kyoto rats on a normal sodium diet (WKYNNa) compared with those given saline to drink for 6 weeks (WKYHNa). 2 The renal cortical vascular responses to the adrenergic agonists noradrenaline (NA), methoxamine (ME) and phenylephrine (PE) were measured in WKYHNa and WKYNNa rats either in the absence (the control phase) or presence of chloroethylclonidine (CEC), an alpha(1B)-adrenoceptor antagonist, 5-methylurapidil (5-MeU), an alpha(1A) antagonist, or BMY7378, an alpha(1D) antagonist. 3 Results showed a greater renal cortical vascular sensitivity to NA, PE and ME in the WKYHNa compared with WKYNNa rats (P < 0.05). Moreover, 5-MeU and BMY7378 attenuated adrenergically induced renal cortical vasoconstriction in WKYHNa and WKYNNa rats; this response was largely blunted in CEC-treated WKYHNa rats (all P < 0.05) but not in CEC-treated WKYNNa rats. 4 The data suggest that irrespective of dietary sodium content, in Wistar-Kyoto rats alpha(1A)- and alpha(1D)-subtypes are the major alpha(1)-adrenoceptors in renal cortical vasculature; however, there appears to be a functional involvement of alpha(1B)-adrenoceptors in the WKYHNa rats.
    Matched MeSH terms: Blood Pressure/drug effects
  19. Inhibition of Ang II and renal sympathetic nerve influence dopamine-and isoprenaline-induced renal haemodynamic changes in normal Wistar-Kyoto and spontaneously hypertensive rats
    Abdulla MH, Sattar MA, Abdullah NA, Hazim AI, Anand Swarup KR, Rathore HA, et al.
    Auton Autacoid Pharmacol, 2008 Oct;28(4):95-101.
    PMID: 18778332 DOI: 10.1111/j.1474-8673.2008.00422.x
    1. This study was undertaken to elucidate the effects of inhibiting the renin-angiotensin system (RAS) with losartan, and acute unilateral renal denervation on renal haemodynamic responses to intrarenal administration of vasoconstrictor doses of dopamine and vasodilator doses of isoprenaline in Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). 2. Acute unilateral renal denervation of the left kidney in rats was confirmed by a drop in the renal vasoconstrictor response to renal nerve stimulation (P < 0.05) along with diuresis and natriuresis. Rats were pretreated with losartan for 7 days and thereafter animals fasted overnight were anaesthetized (sodium pentobarbitone, 60 mg/kg i.p.) and acute renal haemodynamic responses studied. 3. Dose-response curves were constructed for dopamine and isoprenaline that induced falls or increases in renal blood flow, respectively. It was observed that renal vascular responses were greater in the denervated as compared with rats with intact renal nerves (all P < 0.05). Dopamine-induced renal vasoconstrictor responses were markedly lower in losartan-treated denervated WKY and SHR compared with their untreated counterparts (all P < 0.05). It was also observed that in losartan-treated and denervated WKY rats the vasodilatory responses to isoprenaline were markedly lower compared with untreated rats (all P < 0.05). However, in SHR, under the same conditions, there was no difference in the renal response to isoprenaline whether or not rats were treated with losartan (P > 0.05). 4. The data obtained showed that the renal vasoconstrictor effect of dopamine depends on intact renal nerves and RAS in WKY and SHR. Isoprenaline responses were likewise sensitive to renal denervation and RAS inhibition in WKY rats but not SHRs. Our observations reveal a possible relationship between renal AT(1) receptors and alpha(1)-adrenoceptors in WKY and SHR. There is also evidence to suggest an interaction between renal beta-adrenoceptors and AT(1) receptors in WKY rats.
    Matched MeSH terms: Blood Pressure/drug effects
  20. Effect of acute unilateral renal denervation on renal hemodynamics in spontaneously hypertensive rats
    Abdulla MH, Sattar MA, Salman IM, Abdullah NA, Ameer OZ, Khan MA, et al.
    Auton Autacoid Pharmacol, 2008 Apr-Jul;28(2-3):87-94.
    PMID: 18598290 DOI: 10.1111/j.1474-8673.2008.00421.x
    1 This study was undertaken to characterize the renal responses to acute unilateral renal denervation in anaesthetized spontaneously hypertensive rats (SHR) by examining the effect of acute unilateral renal denervation on the renal hemodynamic responses to a set of vasoactive agents and renal nerve stimulation. 2 Twenty-four male SHR rats underwent acute unilateral renal denervation and the denervation was confirmed by significant drop (P < 0.05) in renal vasoconstrictor response to renal nerve stimulation along with marked diuresis and natriuresis following denervation. After 7 days treatment with losartan, the overnight fasted rats were anaesthetized (sodium pentobarbitone, 60 mg kg(-1) i.p.) and renal vasoconstrictor experiments were performed. The changes in the renal vasoconstrictor responses were determined in terms of reductions in renal blood flow caused by renal nerve stimulation or intrarenal administration of noradrenaline, phenylephrine, methoxamine and angiotensin II. 3 The data showed that there was significantly (all P < 0.05) increased renal vascular responsiveness to the vasoactive agents in denervated rats compared to those with intact renal nerves. In losartan-treated denervated SHR rats, there were significant (all P < 0.05) reductions in the renal vasoconstrictor responses to neural stimuli and vasoactive agents as compared with that of untreated denervated SHR rats. 4 The data obtained in denervated rats suggested an enhanced sensitivity of the alpha(1)-adrenoceptors to adrenergic agonists and possible increase of AT(1) receptors functionality in the renal vasculature of these rats. These data also suggested a possible interaction between sympathetic nervous system and renin-angiotensin system in terms of a crosstalk relationship between renal AT(1) and alpha(1)-adrenoceptor subtypes.
    Matched MeSH terms: Blood Pressure/drug effects
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