Displaying publications 1 - 20 of 41 in total

Abstract:
Sort:
  1. Gan EK, Tan JSK
    Med J Malaysia, 1981 Jun;36(2):112-5.
    PMID: 7343819
    Male albino rats were chronically loaded with sodium by giving 1% NaCl solution as the sole source of drinking water. Daily fluid intake, daily urinary output and daily Na+ and K+ excretion rates were compared with control rats receiving tap water for six weeks. At the end ofsix weeks, sodium loaded animals were found to have raised plasma Na+ concentration, lowered plasma K+ concentration and lowered haematocrit value. Sodium loaded rats were also significantly more responsive to the pressor effect of submaximal doses of adrenaline, noradrenaline and angiotensin II given intravenously. It is concluded that the increase in sensitivity to adrenaline and noradrenaline may be due to changes in EGF and alterations of plasma electrolytes concentration. For angiotensin II, additionally, it may be due to low circulating endogenous angiotensin II, consequent of reduction in renin release attributed to chronic sodium loading.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology*
  2. 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: Vasoconstrictor Agents/therapeutic use*
  3. Rehman A, Rahman AR, Rasool AH, Naing NN
    Int J Clin Pharmacol Ther, 2001 Oct;39(10):423-30.
    PMID: 11680667
    To examine the dose response relationship between Ang II and pulse wave velocity (an index of arterial stiffness) in healthy human volunteers.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology*
  4. Rehman A, Rahman AR, Rasool AH
    J Hum Hypertens, 2002 Apr;16(4):261-6.
    PMID: 11967720
    The objective of this study was to examine the effect of angiotensin II (Ang II) and angiotensin II type 1 (AT(1)) receptor blockade on pulse wave velocity (PWV) in healthy humans. We studied nine young male volunteers in a double-blind randomised crossover design. Carotid-femoral PWV (an index of arterial stiffness) was measured by using a Complior machine. Subjects were previously treated for 3 days with once-daily dose of either a placebo or valsartan 80 mg. On the third day, they were infused with either placebo or 5 ng/kg/min of Ang II over 30 min. Subjects thus received placebo capsule + placebo infusion (P), valsartan + placebo infusion (V), placebo + Ang II infusion (A), and valsartan + Ang II infusion (VA) combinations. Heart rate (HR), blood pressure and PWV were recorded at baseline and then every 10 min during infusion and once after the end of infusion. There were significant increases in systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) with A compared with P (P = 0.002, P = 0.002, P = 0.001 respectively). These rises in blood pressure were completely blocked by valsartan. A significant rise in PWV by A was seen compared with P (8.38 +/- 0.24 vs 7.48 +/- 0.24 m/sec, P = 0.013) and was completely blocked by valsartan; VA compared with P (7.27 +/- 0.24 vs 7.48 +/- 0.24 m/sec, P = NS). Multiple linear regression analysis showed that blockade of Ang II induced increase in blood pressure by valsartan contributed to only 30% of the total reduction in Ang II induced rise in PWV (R(2) = 0.306). The conclusions were that valsartan completely blocks the effect of Ang II on PWV. The effect of Ang II on PWV is mediated through AT(1)receptors. Reduction in PWV by Ang II antagonist is not fully explained by its pressure lowering effect of Ang II and may be partially independent of its effect on blood pressure.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology*
  5. Ajay M, Gilani AU, Mustafa MR
    Life Sci, 2003 Dec 19;74(5):603-12.
    PMID: 14623031
    The potency, structure-activity relationship, and mechanism of vasorelaxation of a series of flavonoids, representing different subclasses (flavonols: fisetin, rutin, quercetin; flavones: chrysin, flavone, baicalein; flavanones: naringenin, naringin; isoflavones: diadzein and flavanes: epigallo catechin gallate), were examined in the isolated rat aorta. Most of the flavonoids tested showed concentration dependent relaxant effects against K+ (80 mM) and phenylephrine (PE, 0.1 microM)-induced contractions with a greater inhibition of the responses to the alpha1-adrenoceptor agonist. The relaxant effects of most of the flavonoids involve in part the release of nitric oxide and prostaglandins from the endothelium as pretreatment with L-NAME and indomethacin attenuated the responses. In addition, the relaxant action of the flavonoids includes inhibition of Ca+2 influx and release of Ca+2 from intracellular stores. A structure-activity relationship amongst the flavonoids was suggested.
    Matched MeSH terms: Vasoconstrictor Agents/antagonists & inhibitors; Vasoconstrictor Agents/pharmacology
  6. Mustafa MR, Dharmani M, Kunheen NK, Sim MK
    Regul. Pept., 2004 Aug 15;120(1-3):15-22.
    PMID: 15177916
    An earlier study showed that des-aspartate-angiotensin I (DAA-I) attenuated the pressor action of angiotensin III in aortic rings of the spontaneously hypertensive rat (SHR) but not the normotensive Wistar Kyoto (WKY) rat. The present study investigated similar properties of DAA-I in isolated perfused kidneys and mesenteric beds of WKY and SHR. In the renal vasculature, angiotensin III induced a dose-dependent pressor response, which was more marked in the SHR than WKY in terms of significant greater magnitude of response and lower threshold. DAA-I attenuated the pressor action of angiotensin III in both the WKY and SHR. The attenuation in SHR was much more marked, occurring at doses as low as 10(-15) M DAA-I, while effective attenuation was only seen with 10(-9) M in WKY. The effects of DAA-I was not inhibited by PD123319 and indomethacin, indicating that its action was not mediated by angiotensin AT2 receptors and prostaglandins. However, the direct pressor action of angiotensin III in the SHR but not the WKY was attenuated by indomethacin suggesting that this notable difference could be due to known decreased response of renal vasculature to vasodilator prostaglandins in the SHR. Pressor responses to angiotensin III in the mesenteric vascular bed was also dose dependent, but smaller in magnitude compared to the renal response. The responses in the SHR, though generally smaller, were not significantly different from those of the WKY. This trend is in line with the similar observations with angiotensin III and II by other investigators. In terms of the effect of DAA-I, indomethacin and PD123319 on angiotensin III action, similar patterns to those of the renal vasculature were observed. This reaffirms that in the perfused kidney and mesenteric bed, where the majority of the vessels are contractile, femtomolar concentrations of DAA-I attenuates the pressor action of angiotensin III. The attenuation is not indomethacin sensitive and does not involve the angiotensin AT2 receptor. The findings suggest that DAA-I possesses protective vascular actions and is involved in the pathophysiology of hypertension.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
  7. Machha A, Mustafa MR
    J Cardiovasc Pharmacol, 2005 Jul;46(1):36-40.
    PMID: 15965352
    Flavonoids are known to possess cardioprotective properties. Vascular endothelial function is a surrogate marker for cardiovascular diseases, including hypertension. We have studied the effects of chronic flavonoid treatment on vascular endothelial functions in spontaneously hypertensive rats (SHR). Starting from 6-7 weeks old, SHR were given flavonoids (baicalein, flavone, or quercetin) orally (10 mg/kg, once daily) to the SHRs for 4 weeks. Aortas from all the flavonoid-treated animals showed remarkably higher endothelium-dependent relaxations to acetylcholine, to a similar extent as those pretreated with the angiotensin-converting enzyme inhibitor, captopril. However, in contrast to other experimental groups, flavone pretreatment also enhanced the endothelium-independent relaxations to sodium nitroprusside. In addition, treatment with either flavone or quercetin induced a significant attenuation in systolic blood pressure of the hypertensive animals. The present results suggest that chronic treatment with the flavonoids (baicalein, flavone, and quercetin) preserves vascular endothelial functions in hypertensive animals through several possible actions, including increasing endothelial nitric oxide production and bioavailability and reduction in blood pressure.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
  8. Dharmani M, Mustafa MR, Achike FI, Sim MK
    Regul. Pept., 2005 Jul 15;129(1-3):213-9.
    PMID: 15927718
    The present study investigated the action of des-aspartate-angiotensin I (DAA-I) on the pressor action of angiotensin II in the renal and mesenteric vasculature of WKY, SHR and streptozotocin (STZ)-induced diabetic rats. Angiotensin II-induced a dose-dependent pressor response in the renal vasculature. Compared to the WKY, the pressor response was enhanced in the SHR and reduced in the STZ-induced diabetic rat. DAA-I attenuated the angiotensin II pressor action in renal vasculature of WKY and SHR. The attenuation was observed for DAA-I concentration as low as 10(-18) M and was more prominent in SHR. However, the ability of DAA-I to reduce angiotensin II response was lost in the STZ-induced diabetic kidney. Instead, enhancement of angiotensin II pressor response was seen at the lower doses of the octapeptide. The effect of DAA-I was not inhibited by PD123319, an AT2 receptor antagonist, and indomethacin, a cyclo-oxygenase inhibitor in both WKY and SHR, indicating that its action was not mediated by angiotensin AT2 receptor and prostaglandins. The pressor responses to angiotensin II in mesenteric vascular bed were also dose-dependent but smaller in magnitude compared to the renal vasculature. The responses were significantly smaller in SHR but no significant difference was observed between STZ-induced diabetic and WKY rat. Similarly, PD123319 and indomethacin had no effect on the action of DAA-I. The findings reiterate a regulatory role for DAA-I in vascular bed of the kidney and mesentery. By being active at circulating level, DAA-I subserves a physiological role. This function appears to be present in animals with diseased state of hypertension and diabetes. It is likely that DAA-I functions are modified to accommodate the ongoing vascular remodeling.
    Matched MeSH terms: Vasoconstrictor Agents/administration & dosage*
  9. Hye Khan MA, Abdul Sattar M, Abdullah NA, Johns EJ
    Exp. Toxicol. Pathol., 2007 Nov;59(3-4):253-60.
    PMID: 17764917
    The pathogenesis of cisplatin-induced renal failure is related to reduced renal blood flow due to severe tubular damage and enhanced renovascular resistance. It is also known that alpha(1)-adrenoceptors, the major subtype of alpha-adrenoceptors in renal vasculature play the pivotal role in regulating renal hemodynamics. With this background, we have hypothesized that the altered renal hemodynamics and enhanced renovascular resistance in cisplatin-induced renal failure might be caused by the altered alpha-adrenergic responsiveness with a possible involvement of alpha(1)-adrenoceptors in the renal vasculature. In a unique experimental approach with anesthetized rats, this study has therefore examined if there is any shift in the renovascular responsiveness to renal nerve stimulation and a series of alpha-adrenergic agonists in Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats with cisplatin-induced renal failure in comparison with their body weight-matched normal controls. Thirty-two male rats of both WKY (n=16) and SHR (n=16) origin with body weight 236+/-7.9 g received cisplatin (5mg/kg i.p.). The renal failure was confirmed in terms of significantly reduced renal blood flow, reduced creatinine clearance, increased fractional excretion of sodium, increased kidney index (all P<0.05) and tubular damage. After 7 days of cisplatin, the overnight fasted rats were anesthetized (sodium pentobarbitone, 60 mg/kg i.p.) and renal vasoconstrictor experiments were done. The changes in the vasoconstrictor responses were determined in terms of reductions in renal blood flow caused by electrical renal nerve stimulation or intrarenal administration of noradrenaline, phenylephrine and methoxamine. It was observed that in the cisplatin-treated renal failure WKY and SHR rats there were significant (all P<0.05) reductions in the renal blood flow along with significantly (P<0.05) higher renal adrenergic responsiveness as compared with their non-renal failure controls. The data showed that in the renal failure WKY and SHR rats, the altered renal hemodynamics might be caused by an augmented renal adrenergic responsiveness. The results obtained further led us to suggest that the augmented renal adrenergic responsiveness in the cisplatin-induced renal failure rats were possibly mediated by the alpha(1)-adrenoceptors.
    Matched MeSH terms: Vasoconstrictor Agents/administration & dosage
  10. Armenia, Sattar MA, Abdullah NA, Khan MA, Johns EJ
    Auton Autacoid Pharmacol, 2008 Jan;28(1):1-10.
    PMID: 18257746 DOI: 10.1111/j.1474-8673.2007.00412.x
    1 The present study investigated the effect of streptozotocin-induced diabetes on alpha(1)-adrenoceptor subtypes in rat renal resistance vessels. 2 Studies on renal haemodynamics were carried out 7 days after the last streptozotocin. Changes in renal blood flow were recorded in response to electrical stimulation of the renal nerve (RNS) and a range of adrenergic agonists; noradrenaline (NA), phenylephrine (PE) and methoxamine (MTX), either in the absence or the presence of nitrendipine (Nit), 5-methylurapidil (MEU), chlorethylclonidine (CEC) or BMY 7378. 3 In non-diabetic animals, Nit, MEU and BMY 7378 significantly attenuated renal vasoconstriction induced by adrenergic agonists, while CEC showed a significant accentuation in RNS-induced responses without having a significant effect on responses to adrenergic agonists. In diabetic rats, renal vasoconstriction was also significantly reduced in Nit-, MEU- and BMY 7378-treated groups and CEC potentiated RNS-induced contractions caused a change similar to that observed in non-diabetic rats. BMY 7378 significantly (P < 0.05) attenuated the PE- and MTX-induced vasoconstrictions but did not cause any significant (P > 0.05) alteration in the RNS- and NA-induced responses. 4 The results showed functional co-existence of alpha(1A)- and alpha(1D)-adrenoceptors in the renal vasculature of SD rats irrespective of the presence of diabetes. A possible minor contribution of prejunctional alpha-adrenoceptor subtype has also been suggested in either experimental group, particularly possible functional involvement of alpha(1B)-adrenoceptor subtypes in non-diabetic SD rats.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
  11. 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: Vasoconstrictor Agents/pharmacology
  12. Abdulla MH, Sattar MA, Khan MA, Abdullah NA, Johns EJ
    Acta Physiol (Oxf), 2009 Mar;195(3):397-404.
    PMID: 19183357 DOI: 10.1111/j.1748-1716.2008.01895.x
    This study investigated the influence of angiotensin II (Ang II) receptor and adrenergic blockade on the renal vasoconstrictions caused by Ang II and adrenergic agonists in spontaneously hypertensive rats (SHR).
    Matched MeSH terms: Vasoconstrictor Agents/antagonists & inhibitors; Vasoconstrictor Agents/pharmacology*
  13. Khan MA, Sattar MA, Abdullah NA, Abdulla MH, Salman IM, Kazi RN, et al.
    Kidney Blood Press Res, 2009;32(5):349-59.
    PMID: 19844130 DOI: 10.1159/000249149
    This study investigated the impact of hypertension combined with diabetic nephropathy on rat renal alpha(1)-adrenoceptor subtype composition.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
  14. 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: Vasoconstrictor Agents/antagonists & inhibitors; Vasoconstrictor Agents/pharmacology
  15. Salman IM, Sattar MA, Ameer OZ, Abdullah NA, Yam MF, Salman HM, et al.
    Indian J Med Res, 2010 Jun;131:786-92.
    PMID: 20571167
    A wealth of information concerning the essential role of renal sympathetic nerve activity (RSNA) in the regulation of renal function and mean arterial blood pressure homeostasis has been established. However, many important parameters with which RSNA interacts are yet to be explicitly characterized. Therefore, the present study aimed to investigate the impact of acute renal denervation (ARD) on sodium and water excretory responses to intravenous (iv) infusions of either norepinephrine (NE) or angiotensin II (Ang II) in anaesthetized spontaneously hypertensive rats (SHR).
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
  16. Ameer OZ, Salman IM, Najim HS, Abdullah GZ, Abdulkarim MF, Yam MF, et al.
    J Acupunct Meridian Stud, 2010 Dec;3(4):272-82.
    PMID: 21185543 DOI: 10.1016/S2005-2901(10)60048-9
    The mode by which Loranthus ferrugineus methanol extract antagonizes and/or modulates norepinephrine-induced vasoconstriction was investigated in rat aortic rings. The vascular effects of three different concentrations of this extract were challenged against cumulative additions of norepinephrine. Phentolamine, a nonselective α-adrenoceptor antagonist, verapamil, an L-type calcium channel blocker, and papaverine, a phosphodiesterase inhibitor, were used in three different concentrations as positive controls. Log concentration-response curves and double-reciprocal plots were constructed for the extract and each vasorelaxant. To characterize antagonism reversibility, the norepinephrine maximum contractile effect was examined before extract addition to the aortic ring chamber and after its removal. Phentolamine shifted the norepinephrine log concentration-response curve to the right with no significant depression in the maximum response. Similar to verapamil and papaverine, the extract produced a rightward shift in norepinephrine log concentration-response curve and a significant drop in maximum response. The double-reciprocal plots showed comparable y-intercept values for all phentolamine concentrations, a characteristic of competitive antagonism. In contrast, different y-intercept values on double-reciprocal plots were obtained for each concentration of extract, verapamil, and papaverine, typical of noncompetitive antagonism. The norepinephrine maximum contractile response was approximately similar before the addition of extract and after its removal. The data collectively showed that L. ferrugineus methanol extract exerted its vascular effect by reversible noncompetitive antagonism of norepinephrine-induced vasoconstriction. These findings add to the understanding of the cardiovascular mechanisms by which L. ferrugineus, a plant traditionally used for the management of hypertension, elicits its action.
    Matched MeSH terms: Vasoconstrictor Agents/antagonists & inhibitors*; Vasoconstrictor Agents/pharmacology
  17. Lim YL, Mok SL
    Med Princ Pract, 2010;19(4):260-8.
    PMID: 20516701 DOI: 10.1159/000312711
    To investigate the antihypertensive activity of aqueous extracts obtained from Malaysian coastal seaweeds and to determine the pharmacological mechanisms of the extracts on rat aorta in vitro.
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
  18. Beale R, Janes JM, Brunkhorst FM, Dobb G, Levy MM, Martin GS, et al.
    Crit Care, 2010;14(3):R102.
    PMID: 20525247 DOI: 10.1186/cc9044
    INTRODUCTION: The benefits and use of low-dose corticosteroids (LDCs) in severe sepsis and septic shock remain controversial. Surviving sepsis campaign guidelines suggest LDC use for septic shock patients poorly responsive to fluid resuscitation and vasopressor therapy. Their use is suspected to be wide-spread, but paucity of data regarding global practice exists. The purpose of this study was to compare baseline characteristics and clinical outcomes of patients treated or not treated with LDC from the international PROGRESS (PROmoting Global Research Excellence in Severe Sepsis) cohort study of severe sepsis.

    METHODS: Patients enrolled in the PROGRESS registry were evaluated for use of vasopressor and LDC (equivalent or lesser potency to hydrocortisone 50 mg six-hourly plus 50 microg 9-alpha-fludrocortisone) for treatment of severe sepsis at any time in intensive care units (ICUs). Baseline characteristics and hospital mortality were analyzed, and logistic regression techniques used to develop propensity score and outcome models adjusted for baseline imbalances between groups.

    RESULTS: A total of 8,968 patients with severe sepsis and sufficient data for analysis were studied. A total of 79.8% (7,160/8,968) of patients received vasopressors, and 34.0% (3,051/8,968) of patients received LDC. Regional use of LDC was highest in Europe (51.1%) and lowest in Asia (21.6%). Country use was highest in Brazil (62.9%) and lowest in Malaysia (9.0%). A total of 14.2% of patients on LDC were not receiving any vasopressor therapy. LDC patients were older, had more co-morbidities and higher disease severity scores. Patients receiving LDC spent longer in ICU than patients who did not (median of 12 versus 8 days; P <0.001). Overall hospital mortality rates were greater in the LDC than in the non-LDC group (58.0% versus 43.0%; P <0.001). After adjusting for baseline imbalances, in all mortality models (with vasopressor use), a consistent association remained between LDC and hospital mortality (odds ratios varying from 1.30 to 1.47).

    CONCLUSIONS: Widespread use of LDC for the treatment of severe sepsis with significant regional and country variation exists. In this study, 14.2% of patients received LDC despite the absence of evidence of shock. Hospital mortality was higher in the LDC group and remained higher after adjustment for key determinates of mortality.

    Matched MeSH terms: Vasoconstrictor Agents/administration & dosage; Vasoconstrictor Agents/pharmacology; Vasoconstrictor Agents/therapeutic use*
  19. Abdulla MH, Sattar MA, Abdullah NA, Hye Khan MA, Anand Swarup KR, Johns EJ
    Eur J Nutr, 2011 Jun;50(4):251-60.
    PMID: 20882287 DOI: 10.1007/s00394-010-0133-8
    PURPOSE: Fructose feeding induces a moderate increase in blood pressure, insulin resistance, and hyperinsulinemia. This study investigated the role of α(1B)-adrenoceptor subtype in the control of renal hemodynamic responses to exogenously administered angiotensin II (Ang II) and a set of adrenergic agonists in a model of high fructose-fed rats.
    METHODS: Sprague-Dawley rats were fed for 8 weeks with 20% fructose in drinking water (FFR). The renal cortical vasoconstriction to noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II in the presence and absence of chloroethylclonidine (CEC) (α(1B)-adrenoceptor antagonist) was determined. Data, mean ± SEM or SD were subjected to ANOVA with significance at p 
    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
  20. Abdulla MH, Sattar MA, Johns EJ, Abdullah NA, Khan MA
    Eur J Nutr, 2011 Dec;50(8):689-97.
    PMID: 21373947 DOI: 10.1007/s00394-011-0180-9
    AIM: To explore the hypothesis that high fructose intake results in a higher functional contribution of α1A-adrenoceptors and blunts the adrenergically and angiotensin II (Ang II)-induced renal vasoconstriction.

    METHODS: Twelve Sprague-Dawley rats received either 20% fructose solution [FFR] or tap water [C] to drink ad libitum for 8 weeks. The renal vasoconstrictor response to noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II was determined in the presence and absence of 5-methylurapidil (5-MU) (α1A-adrenoceptor antagonist) in a three-phase experiment (pre-drug, low- and high-dose 5-MU). Data, mean ± SEM were analysed by ANOVA or Student's unpaired t-test with significance at P < 0.05.

    RESULTS: FFR exhibited insulin resistance (HOMA index), hypertension and significant increases in plasma levels of glucose and insulin. All agonists caused dose-related reductions in cortical blood perfusion that were larger in C than in FFR while the magnitudes of the responses were progressively reduced with increasing doses of 5-MU in both C and FFR. The degree of 5-MU attenuation of the renal cortical vasoconstriction due to NA, ME and Ang II was significantly greater in the FFR compared to C.

    CONCLUSIONS: Fructose intake for 8 weeks results in smaller vascular response to adrenergic agonists and Ang II. The α1A-adrenoceptor subtype is the functional subtype that mediates renal cortical vasoconstriction in control rats, and this contribution becomes higher due to fructose feeding.

    Matched MeSH terms: Vasoconstrictor Agents/pharmacology
Filters
Contact Us

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

External Links