Displaying publications 1 - 20 of 25 in total

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  1. Belqes Abdullah, A. T., Yvonne, T. G. B., Ahmad, S. H., Abdul Aziz, A. S. I., Aida, H. G. R.
    MyJurnal
    Introduction: Iontophoresis of vasoactive substances such as acetylcholine (ACh) and sodium nitroprusside (SNP) combined with Laser Doppler fluximetry (LDF) is a non-invasive tool used to determine microvascular endothelial function. This study aims to test the effect of sodium chloride on
    non-specific vasodilatation when used as a vehicle in the process of iontophoresis. This study also aims to define the number of current pulses needed to get the maximum effect during iontophoresis with ACh and SNP using low current strength. Methods: The experiment was conducted in five healthy females. Baseline skin perfusion was taken before administration of seven current pulses. Current strength of 0.007 mA and current density of 0.01 mA/cm2 were used. Acetylcholine was used to assess endothelial dependent vasodilatation, while SNP was used to assess endothelial independent vasodilatation. The mean skin perfusion (AU) responses to the iontophoresis of ACh at the anodal and SNP at the cathode leads were recorded. Sodium chloride (0.9%) was used as a vehicle to obtain concentration of 1% for both ACh and SNP. Iontophoresis of pure vehicle (NaCl) was conducted on a separate day to observe the effect of vehicle only on the iontophoresis process at both anode and cathode. Results: Iontophoresis of NaCl showed no significant increase in perfusion compared to baseline at both anode and cathode. Significant increases in skin perfusion were observed with SNP and ACh; a plateau of ACh was reached from the 3rd pulse onwards; while the plateau of SNP was reached from the 4th pulse onwards. Conclusion: NaCl could be used as a vehicle for Ach and SNP during iontophoresis as it did not cause non-specific vasodilatation. Using five current pulses are adequate for iontophoresis of ACh and SNP to assess microvascular endothelial function.
    Matched MeSH terms: Nitroprusside
  2. Li Tian, Xiao-yun Huang, Qiang-sheng Wu, Nasrullah
    Sains Malaysiana, 2017;46:1687-1691.
    Arbuscular mycorrhizal fungi (AMF) actively colonize plant roots and thus enhance plant growth through different mechanisms. In the present study, trifoliate orange (Poncirus trifoliata) seedlings inoculated with Diversispora versiformis were subjected to 0 and 0.2 mmol/L sodium nitroprusside (SNP, a nitric oxide donor) treatments. After eight weeks, exogenous SNP considerably increased root mycorrhizal colonization by 25%, showing a positive stimulating effect of NO on mycorrhizal formation. Mycorrhizal inoculation significantly increased plant growth performance (height, stem diameter, leaf number and shoot and root dry weight) and root traits (length, projected area, surface area, volume and number of 2nd and 3rd order lateral roots) than non-mycorrhizal treatment and NO (exogenous SNP treatment) heavily strengthened the mycorrhizal effects. Moreover, NO and mycorrhization induced more fine root (0-0.5 cm) formation. There was an opposite changed trend in root sucrose and leaf and root glucose contents by SNP in AMF versus non-AMF seedlings. All these results implied that NO plays important roles in mycorrhizal formation and development and also accelerates mycorrhizal effects on plant growth and root development of trifoliate orange.
    Matched MeSH terms: Nitroprusside
  3. Al-Tahami BA, Yvonne-Tee GB, Halim AS, Ismail AA, Rasool AH
    Methods Find Exp Clin Pharmacol, 2010 Apr;32(3):181-5.
    PMID: 20448860 DOI: 10.1358/mf.2010.32.3.1423887
    Iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) combined with laser Doppler fluximetry (LDF) is a tool used to determine microvascular endothelial function. Our aim was to study the reproducibility of different parameters of this technique using iontophoresis with low current strength on the forearm skin of healthy subjects. Baseline skin perfusion was done before application of five current pulses with 1 min of current-free interval. Current strength of 0.007 mA, current density of 0.01 mA/cm(2) and charge density of 6 mC/cm(2) were used, along with 1% ACh and 1% SNP. The absolute maximum change in perfusion (max), percent change in perfusion (% change), peak change in perfusion (peak) and area under the curve during iontophoresis (AUC) at the anodal and cathodal leads were recorded. Measurements were performed in three sessions for 2 days. The coefficient of variation (CV) was calculated for each parameter. Among the parameters studied, maximum change in perfusion and peak flux were the most reproducible parameters.
    Matched MeSH terms: Nitroprusside/pharmacokinetics
  4. Kunasegaran T, Mustafa MR, Achike FI, Murugan DD
    Eur J Pharmacol, 2017 Mar 15;799:160-170.
    PMID: 28213289 DOI: 10.1016/j.ejphar.2017.02.022
    Pioglitazone is an anti-diabetic drug with potential to cause adverse effects following prolonged use. This study, therefore, investigated the effects of combination treatment of a subliminal concentration of pioglitazone and quercetin, a potent antioxidant, on vascular reactivity of aorta isolated from fructose-streptozotocin (F-STZ)-induced diabetic rats. Relaxation to acetylcholine and sodium nitroprusside, and contraction to phenylephrine were tested in organ bath chambers following pre-incubation with vehicle (DMSO; 0.05%), quercetin (10-7 M), pioglitazone (10-7 M), or their combination (P+Q; 10-7 M each drug). Subliminal concentration of quercetin or pioglitazone did not alter the acetylcholine- induced relaxation nor the phenylephrine-induced contraction in both normal rat and diabetic F-STZ induced tissues. However, P+Q combination synergistically improved the impaired acetylcholine-induced relaxation and decreased the elevated phenylephrine-induced contraction in aortic rings from diabetic, but not in the normal rats. Neither mono nor combination treatment altered sodium nitroprusside-induced relaxation. The combination also synergistically decreased superoxide anion and increased nitric oxide production compared to the individual treatments in aorta from diabetic rats. Overall, these data demonstrated a synergistic effect, in which, a combination (P+Q; 10-7 M each drug) caused a significantly greater effect than 10-6 M of either agent in improving endothelial function of isolated diabetic aorta. In conclusion, a combination of subliminal concentrations of pioglitazone and quercetin is able to decrease oxidative stress and provide synergistic vascular protection in type 2 diabetes mellitus and thus the possibility of using quercetin as a supplement to pioglitazone in the treatment of diabetes with the goal of reducing pioglitazone toxicity.
    Matched MeSH terms: Nitroprusside
  5. Sadeghipour O
    Sains Malaysiana, 2017;46:189-195.
    Lead (Pb) is one of the most abundant toxic heavy metals which adversely affected growth and yield of crop plants. Nitric oxide (NO), an endogenous signaling molecule, has been suggested to be involved in defense responses to biotic and abiotic stresses in plants. The present study was done to induce Pb tolerance in cowpea plants by exogenous NO application using two levels of Pb, 0 and 200 mg Pb (NO3)2 kg-1 soil and three NO levels, 0, 0.5 and 1 mM sodium nitroprusside (SNP), as NO donor. The results showed that Pb treatment caused a significant increase in Pb concentration in all plant parts. Roots had higher levels of Pb than the stems, leaves and seeds. Furthermore, lead toxicity reduced auxin (IAA), cytokinin and gibberellic acid (GA3) content but increased abscisic acid (ABA) level. Moreover Pb stress decreased stomatal conductance, leaf area and consequently seed yield of cowpea. Exogenous application of NO at 0.5 mM noticeably alleviated the lead toxicity by improving the leaf area, stomatal conductance and seed yield. NO increased Pb tolerance by lowering Pb uptake and translocation, enhancing the promoting phytohormone (IAA, cytokinin and GA3) level and reducing ABA content.
    Matched MeSH terms: Nitroprusside
  6. Nurul-Iman BS, Kamisah Y, Jaarin K, Qodriyah HM
    PMID: 23861707 DOI: 10.1155/2013/629329
    This study was performed to explore the effects of virgin coconut oil (VCO) in male rats that were fed with repeatedly heated palm oil on blood pressure, plasma nitric oxide level, and vascular reactivity. Thirty-two male Sprague-Dawley rats were divided into four groups: (i) control (basal diet), (ii) VCO (1.42 mL/kg, oral), (iii) five-times-heated palm oil (15%) (5HPO), and (iv) five-times-heated palm oil (15%) and VCO (1.42 mL/kg, oral) (5HPO + VCO). Blood pressure was significantly increased in the group that was given the 5HPO diet compared to the control group. Blood pressure in the 5HPO + VCO group was significantly lower than the 5HPO group. Plasma nitric oxide (NO) level in the 5HPO group was significantly lower compared to the control group, whereas in the 5HPO + VCO group, the plasma NO level was significantly higher compared to the 5HPO group. Aortic rings from the 5HPO group exhibited attenuated relaxation in response to acetylcholine and sodium nitroprusside as well as increased vasoconstriction to phenylephrine compared to the control group. Aortic rings from the 5HPO + VCO group showed only attenuated vasoconstriction to phenylephrine compared to the 5HPO group. In conclusion, VCO prevents blood pressure elevation and improves endothelial functions in rats fed with repeatedly heated palm oil.
    Matched MeSH terms: Nitroprusside
  7. Mohebbati R, Kamkar-Del Y, Shafei MN
    Malays J Med Sci, 2020 May;27(3):43-52.
    PMID: 32684805 DOI: 10.21315/mjms2020.27.3.5
    Background: Ziziphus jujuba Mill (ZJ) is a plant with anti-hypertensive property. In this regard, the present study investigated the effect of aqueous and ethyl acetate fractions of ZJ extract on acute hypertension (HTN) induced by nitro-L-arginine methyl ester (L-NAME).

    Methods: The current study was carried on 49 hypertensive rats divided into seven groups, including i) control; ii) L-NAME (10 mg/kg); iii) sodium nitroprusside (SNP) (50 μg/kg) plus L-NAME; iv and v) aqueous fraction of ZJ (150 mg/kg and 300 mg/kg) plus L-NAME; vi) and vii) ethyl acetate fractions of ZJ (150 mg/kg and 300 mg/kg) plus L-NAME. The rats were orally treated with both fractions for four weeks and received intravenous L-NAME on the 28th day. The mean arterial pressure (MAP), systolic blood pressure (SBP) and heart rate (HR) of the rats were recorded then maximal changes (Δ) of MAP, SBP and HR were calculated and compared with changes of control and L-NAME.

    Results: According to the obtained results of the present study, it was shown that the administration of L-NAME significantly increased ΔMAP, ΔSBP and ΔHR, and these effects were significantly attenuated by administration of SNP. The pre-treatment with both doses (150 mg/kg and 300 mg/kg) of aqueous and ethyl acetate fractions could significantly reduce cardiovascular responses induced by L-NAME that comparable with SNP. However, a lower dose of aqueous fractions and higher dose of ethyl acetate fractions were reported with stronger effects.

    Conclusion: The results of the current study showed that both the aqueous and ethyl acetate fractions of ZJ through the effect on nitric oxide system can prevent the development of HTN induced by L-NAME.

    Matched MeSH terms: Nitroprusside
  8. Ajay M, Achike FI, Mustafa AM, Mustafa MR
    Diabetes Res Clin Pract, 2006 Jul;73(1):1-7.
    PMID: 16378655 DOI: 10.1016/j.diabres.2005.11.004
    The present work examined ex vivo the acute effect of quercetin on diabetic rat aortic ring reactivity in response to endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside, SNP) relaxants, and to the alpha(1)-adrenergic agonist phenylephrine (PE). Responses were compared to those of aortic rings from age- and sex-matched euglycemic rats. Compared to euglycemic rat aortic rings, diabetic rings showed less relaxation in response to ACh and SNP, and greater contraction in response to PE. Pretreatment with quercetin (10microM, 20min) increased ACh-induced relaxation and decreased PE-induced contraction in diabetic, but did not affect euglycemic rat aortic ring responses. Following pretreatment with the nitric oxide synthase inhibitor Nomega-nitro-l-arginine methyl ester (l-NAME, 10microM), quercetin reduced PE-induced contractions in both aortic ring types, although l-NAME attenuated the reduction in the diabetic rings. Quercetin did not alter SNP vasodilatory effects in either ring type compared to their respective controls. These findings indicate that quercetin acutely improved vascular responsiveness in blood vessels from diabetic rats, and that these effects were mediated, at least in part, by enhanced endothelial nitric oxide bioavailability. These effects of quercetin suggest the possible beneficial effects of quercetin in vivo in experimental diabetes and possibly in other cardiovascular diseases.
    Matched MeSH terms: Nitroprusside/pharmacology
  9. Lim E, Dokos S, Salamonsen RF, Rosenfeldt FL, Ayre PJ, Lovell NH
    Artif Organs, 2012 May;36(5):E110-24.
    PMID: 22489799 DOI: 10.1111/j.1525-1594.2012.01449.x
    A heart-pump interaction model has been developed based on animal experimental measurements obtained with a rotary blood pump in situ. Five canine experiments were performed to investigate the interaction between the cardiovascular system and the implantable rotary blood pump over a wide range of operating conditions, including variations in cardiac contractility and heart rate, systemic vascular resistance (SVR), and total blood volume (V(total) ). It was observed in our experiments that SVR decreased with increasing mean pump speed under the healthy condition, but was relatively constant during the speed ramp study under reduced cardiac contractility conditions. Furthermore, we also found a significant increase in pulmonary vascular resistance with increasing mean pump speed and decreasing total blood volume, despite a relatively constant SVR. Least squares parameter estimation methods were utilized to fit a subset of model parameters in order to achieve better agreement with the experimental data and to evaluate the robustness and validity of the model under various operating conditions. The fitted model produced reasonable agreement with the experimental measurements, both in terms of mean values and steady-state waveforms. In addition, all the optimized parameters were within physiological limits.
    Matched MeSH terms: Nitroprusside/pharmacology
  10. Lau YS, Machha A, Achike FI, Murugan D, Mustafa MR
    Exp Biol Med (Maywood), 2012 Jan;237(1):93-8.
    PMID: 22156043 DOI: 10.1258/ebm.2011.011145
    Boldine, a major aporphine alkaloid found in Chilean boldo tree, is a potent antioxidant. Oxidative stress plays a detrimental role in the pathogenesis of endothelial dysfunction in hypertension. In the present study, we investigated the effects of boldine on endothelial dysfunction in hypertension using spontaneously hypertensive rats (SHR), the most studied animal model of hypertension. SHR and their age-matched normotensive Wistar-Kyoto (WKY) rats were treated with boldine (20 mg/kg per day) or its vehicle, which served as control, for seven days. Control SHR displayed higher systolic blood pressure (SBP), reduced endothelium-dependent aortic relaxation to acetylcholine (ACh), marginally attenuated endothelium-independent aortic relaxation to sodium nitroprusside (SNP), increased aortic superoxide and peroxynitrite production, and enhanced p47(phox) protein expression as compared with control WKY rats. Boldine treatment significantly lowered SBP in SHR but not in WKY. Boldine treatment enhanced the maximal relaxation to ACh in SHR, but had no effect in WKY, whereas the sensitivity to ACh was increased in both SHR and WKY aortas. Boldine treatment enhanced sensitivity, but was without effect on maximal aortic relaxation responses, to SNP in both WKY and SHR aortas. In addition, boldine treatment lowered aortic superoxide and peroxynitrite production and downregulated p47(phox) protein expression in SHR aortas, but had no effect in the WKY control. These results show that boldine treatment exerts endothelial protective effects in hypertension, achieved, at least in part, through the inhibition of NADPH-mediated superoxide production.
    Matched MeSH terms: Nitroprusside/pharmacology
  11. Leong XF, Najib MN, Das S, Mustafa MR, Jaarin K
    Tohoku J. Exp. Med., 2009 Sep;219(1):71-8.
    PMID: 19713687
    Oxidization of dietary cooking oil increases the risk of cardiovascular diseases such as hypertension by increasing the formation oxidative oxygen radicals. The aim of study was to investigate the effects of repeatedly heated palm oil on blood pressure, plasma nitrites, and vascular reactivity. Nitrites were measured, as an indirect marker for nitric oxide production. Male Sprague-Dawley rats were divided into four groups: control group fed with basal diet and other three groups fortified with 15% weight/weight fresh palm oil (FPO), palm oil heated five times (5HPO) or palm oil heated ten times (10HPO) for 24 weeks. The oil was heated to 180 degrees C for 10 min. Blood pressure was measured at baseline and at intervals of four weeks for 24 weeks using non-invasive tail-cuff method. Following 24 weeks, the rats were sacrificed and thoracic aortas were dissected for measurement of vascular reactivity. Blood pressure was elevated significantly (p < 0.05) in 5HPO and 10HPO groups, with the 10HPO group showing higher values. Aortic rings from animals fed with heated oil showed diminished relaxation in response to acetylcholine or sodium nitroprusside, and greater contraction to phenylephrine. Acetylcholine and sodium nitroprusside cause endothelium-dependent and endothelium-independent relaxation, respectively. Relaxation responses remained unaltered in the FPO group, with the attenuated contractile response to phenylephrine, compared to control group. FPO increased plasma nitrites by 28%, whereas 5HPO and 10HPO reduced them by 25% and 33%, respectively. Intake of repeatedly heated palm oil causes an increase in blood pressure, which may be accounted for by the attenuated endothelium-dependent vasorelaxant response.
    Matched MeSH terms: Nitroprusside/pharmacology
  12. Machha A, Achike FI, Mohd MA, Mustafa MR
    Eur J Pharmacol, 2007 Jun 22;565(1-3):144-50.
    PMID: 17442302
    Acute exposure to the flavonoid baicalein inhibited endothelium-dependent relaxation in physiological arteries, although the mechanisms are not fully understood. We investigated the effect of baicalein on vascular tone in Wistar-Kyoto (WKY) rat isolated aortic rings in the presence and absence of oxidative stress to further determine the underlying mechanisms. Exposure to baicalein (10 microM) completely abolished endothelium-dependent relaxation induced by acetylcholine and attenuated significantly the endothelium-independent relaxation induced by sodium nitroprusside. Baicalein, similar to Nomega-nitro-L-arginine methyl ester (L-NAME, 10 microM), potentiated significantly the contractile response of aortic rings to alpha1-adrenoceptor agonist phenylephrine. In the presence of L-NAME the baicalein effect on phenylphrine contraction or acetylcholine relaxation was unaltered, suggesting that these effects of baicalein are (like L-NAME effect) endothelial nitric oxide synthase (eNOS)/endothelium-derived nitric oxide-dependent. Inhibition of cyclooxygenase activity with indomethacin (10 microM) or scavenging of superoxide anions with superoxide dismutase (150 units/ml), but not scavenging of hydrogen peroxide with catalase (800 units/ml), enhanced significantly by an essentially similar extent the relaxation to acetylcholine in baicalein-pretreated aortic rings. Relaxant effect to acetylcholine was significantly attenuated in control aortic rings, but was completely abolished in baicalein-pretreated aortic rings in the presence of reduced form of beta-nicotinamide adenine di-nucleotide (beta-NADH, 300 microM). Baicalein blocked beta-NADH (300 microM)-induced transient contractions, suggesting that baicalein may have inhibited activity of NADH/NADPH-oxidase. Baicalein did not alter the failure of acetylcholine to induce relaxation in the presence of pyrogallol (300 microM). In summary, acute exposure to baicalein impairs eNOS/endothelium-derived nitric oxide-mediated vascular tone in rat aortas through the inhibition of endothelium-derived nitric oxide bioavailability coupled to reduced bioactivity of endothelium-derived nitric oxide and to cyclooxygenase-mediated release of superoxide anions.
    Matched MeSH terms: Nitroprusside/pharmacology
  13. Ajay M, Chai HJ, Mustafa AM, Gilani AH, Mustafa MR
    J Ethnopharmacol, 2007 Feb 12;109(3):388-93.
    PMID: 16973321
    Previous studies have demonstrated the anti-hypertensive effects of Hibiscus sabdariffa L. (HS) in both humans and experimental animals. To explore the mechanisms of the anti-hypertensive effect of the HS, we examined the effects of a crude methanolic extract of the calyces of HS (HSE) on vascular reactivity in isolated aortas from spontaneously hypertensive rats. HSE relaxed, concentration-dependently, KCl (high K(+), 80 mM)- and phenylephrine (PE, 1 microM)-pre-contracted aortic rings, with a greater potency against the alpha(1)-adrenergic receptor agonist. The relaxant effect of HSE was partly dependent on the presence of a functional endothelium as the action was significantly reduced in endothelium-denuded aortic rings. Pretreatment with atropine (1 microM), L-NAME (10 microM) or methylene blue (10 microM), but not indomethacin (10 microM), significantly blocked the relaxant effects of HSE. Endothelium-dependent and -independent relaxations induced by acetylcholine and sodium nitroprusside, respectively, were significantly enhanced in aortic rings pretreated with HSE when compared to those observed in control aortic rings. The present results demonstrated that HSE has a vasodilator effect in the isolated aortic rings of hypertensive rats. These effects are probably mediated through the endothelium-derived nitric oxide-cGMP-relaxant pathway and inhibition of calcium (Ca(2+))-influx into vascular smooth muscle cells. The present data further supports previous in vivo findings and the traditional use of HS as an anti-hypertensive agent.
    Matched MeSH terms: Nitroprusside/pharmacology
  14. 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: Nitroprusside/pharmacology
  15. Ng CT, Fong LY, Low YY, Ban J, Hakim MN, Ahmad Z
    Physiol Res, 2016 12 13;65(6):1053-1058.
    PMID: 27539106
    The endothelial barrier function is tightly controlled by a broad range of signaling cascades including nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway. It has been proposed that disturbances in NO and cGMP production could interfere with proper endothelial barrier function. In this study, we assessed the effect of interferon-gamma (IFN-gamma), a pro-inflammatory cytokine, on NO and cGMP levels and examined the mechanisms by which NO and cGMP regulate the IFN-gamma-mediated HUVECs hyperpermeability. The flux of fluorescein isothiocyanate-labeled dextran across cell monolayers was used to study the permeability of endothelial cells. Here, we found that IFN-gamma significantly attenuated basal NO concentration and the increased NO levels supplied by a NO donor, sodium nitroprusside (SNP). Besides, application of IFN-gamma also significantly attenuated both the basal cGMP concentration and the increased cGMP production donated by a cell permeable cGMP analogue, 8-bromo-cyclic GMP (8-Br-cGMP). In addition, exposure of the cell monolayer to IFN-gamma significantly increased HUVECs basal permeability. However, L-NAME pretreatment did not suppress IFN-gamma-induced HUVECs hyperpermeability. L-NAME pretreatment followed by SNP or SNP pretreatment partially reduced IFN-gamma-induced HUVECs hyperpermeability. Pretreatment with a guanylate cyclase inhibitor, 6-anilino-5,8-quinolinedione (LY83583), led to a further increase in IFN-gamma-induced HUVECs hyperpermeability. The findings suggest that the mechanism underlying IFN-gamma-induced increased HUVECs permeability is partly related to the inhibition of NO production.
    Matched MeSH terms: Nitroprusside/pharmacology
  16. Ajay M, Mustafa MR
    Vascul. Pharmacol., 2006 Aug;45(2):127-33.
    PMID: 16807125 DOI: 10.1016/j.vph.2006.05.001
    Impaired vascular reactivity is a hallmark of several cardiovascular diseases that include hypertension and diabetes. This study compared the changes in vascular reactivity in age-matched experimental hypertension and diabetes, and, subsequently, tested whether these changes could be affected directly by ascorbic acid (10 microM). Endothelium-derived nitric oxide (NO) modulation of ascorbic acid effects was also investigated. All the experiments were performed in the presence of a cyclooxygenase inhibitor, indomethacin (10 microM). Results showed that the endothelium-dependent and -independent relaxations induced by acetylcholine (ACh) and sodium nitroprusside (SNP), respectively, were blunted to a similar extent in isolated aortic rings from age-matched spontaneously hypertensive (SHR) (R(max): ACh = 72.83+/-1.86%, SNP = 96.6+/-1.90%) and diabetic (Rmax: ACh = 64.09+/-5.14%, SNP = 95.84+/-1.41%) rats compared with aortic rings of normal rats (Rmax: ACh = 89%, SNP = 104.0+/-1.0%). The alpha1-receptor-mediated contractions induced by phenylephrine (PE) were augmented in diabetic (Cmax = 148.8+/-9.0%) rat aortic rings compared to both normal (Cmax = 127+/-6.9%) and SHR (Cmax = 118+/-4.5%) aortic rings. Ascorbic acid pretreatment was without any significant effects on the vascular responses to ACh, SNP and PE in aortic rings from normal rats. Ascorbic acid significantly improved ACh-induced relaxations in SHR (Rmax = 89.09+/-2.82%) aortic rings to a level similar to that observed in normal aortic rings, but this enhancement in ACh-induced relaxations was only partial in diabetic aortic rings. Ascorbic acid lacked any effects on SNP-induced relaxations in both SHR and diabetic aortic rings. Ascorbic acid markedly attenuated contractions induced by PE in aortic rings from both SHR (Cmax = 92.9+/-6.68%) and diabetic (Cmax = 116.9+/-9.4%) rats. Additionally, following inhibition of nitric oxide synthesis with l-NAME, ascorbic acid attenuated PE-induced contractions in all aortic ring types studied. These results suggest that (1) vascular hyper-responsiveness to alpha(1)-receptor agonists in diabetic arteries is independent of endothelial nitric oxide dysfunction; (2) ascorbic acid directly modulates contractile responses of hypertensive and diabetic rat aortas, likely through mechanisms in part independent of preservation of endothelium-derived nitric oxide.
    Matched MeSH terms: Nitroprusside/pharmacology
  17. Jaarin K, Mustafa MR, Leong XF
    Clinics (Sao Paulo), 2011;66(12):2125-32.
    PMID: 22189740
    OBJECTIVES: The goal of this study was to determine the possible mechanism that is involved in the blood pressure-raising effect of heated vegetable oils.

    METHODS: Adult male Sprague-Dawley rats were divided into 11 groups; the control group was fed with rat chow, and the other groups were fed with chow that was mixed with 15% weight/weight palm or soy oils, which were either in a fresh form or heated once, twice, five, or ten times. Blood pressures were measured at the baseline and throughout the 24-week study. Plasma nitric oxide levels were assessed prior to treatment and at the end of the study. Following 24 weeks, the rats were sacrificed to investigate their vascular reactivity using the thoracic aorta.

    RESULTS: Palm and soy oils had no detrimental effects on blood pressure, and they significantly elevated the nitric oxide contents and reduced the contractile responses to phenylephrine. However, trials using palm and soy oils that were repeatedly heated showed an increase in blood pressure, enhanced phenylephrine-induced contractions, reduced acetylcholine- and sodium nitroprusside-induced relaxations relative to the control and rats that were fed fresh vegetable oils.

    CONCLUSIONS: The blood pressure-raising effect of the heated vegetable cooking oils is associated with increased vascular reactivity and a reduction in nitric oxide levels. The chronic consumption of heated vegetable oils leads to disturbances in endogenous vascular regulatory substances, such as nitric oxide. The thermal oxidation of the cooking oils promotes the generation of free radicals and may play an important contributory role in the pathogenesis of hypertension in rats.

    Matched MeSH terms: Nitroprusside/pharmacology
  18. Sanip Z, Hanaffi SH, Ahmad I, Yusoff SS, Rasool AH, Yusoff HM
    Tob Induc Dis, 2015;13(1):32.
    PMID: 26346914 DOI: 10.1186/s12971-015-0052-9
    BACKGROUND: Studies have demonstrated that secondhand smoke (SHS) exposure could impair endothelial function. However, the effect of SHS exposure specifically on microvascular endothelial function is not well understood. This study aimed to determine the effects of SHS exposure on microvascular endothelial function among non-smoking, generally healthy women.

    FINDINGS: We studied 127 women; and based on their hair nicotine levels measured using gas chromatography-mass spectrometry, 25 of them were categorized as having higher hair nicotine levels, 25 were grouped as having lower hair nicotine and 77 women were grouped into the non-detected group. The non-detected group did not have detectable levels of hair nicotine. Anthropometry, blood pressure (BP), lipid profile and high-sensitivity C-reactive protein (hsCRP) were measured accordingly. Microvascular endothelial function was assessed non-invasively using laser Doppler fluximetry and the process of iontophoresis involving acetylcholine and sodium nitroprusside as endothelium-dependent and endothelium-independent vasodilators respectively. The mean hair nicotine levels for higher and lower hair nicotine groups were 0.74 (1.04) and 0.05 (0.01) ng/mg respectively. There were no significant differences in anthropometry, BP, lipid profile and hsCRP between these groups. There were also no significant differences in the microvascular perfusion and endothelial function between these groups.

    CONCLUSION: In this study, generally healthy non-smoking women who have higher, lower and non-detected hair nicotine levels did not show significant differences in their microvascular endothelial function. Low levels of SHS exposure among generally healthy non-smoking women may not significantly impair their microvascular endothelial function.

    Matched MeSH terms: Nitroprusside
  19. Mudassar Imran Bukhari S, Yew KK, Thambiraja R, Sulong S, Ghulam Rasool AH, Ahmad Tajudin LS
    Ther Adv Ophthalmol, 2019 08 22;11:2515841419868100.
    PMID: 31489400 DOI: 10.1177/2515841419868100
    Purpose: To determine the role of microvascular endothelial dysfunction as risk factor for primary open angle glaucoma.

    Methods: A cross-sectional study was conducted involving 114 Malay patients with POAG seen at the eye clinic of Hospital Universiti Sains Malaysia. Patients aged between 40 and 80 years who were diagnosed with other types of glaucoma, previous glaucoma filtering surgery or other surgeries except uncomplicated cataract surgery and pterygium surgery were excluded. A total of 101 patients who were followed up for dry eyes, age-related cataracts or post cataracts extraction surgery were recruited as control subjects. Those with family history of glaucoma or glaucoma suspect were excluded. Microvascular endothelial function was assessed using laser Doppler fluximetry and the process of iontophoresis. Iontophoresis with acetylcholine (ACh) and sodium nitroprusside (SNP) was used to measure microvascular endothelium-dependent and endothelium-independent vasodilatations, respectively.

    Results: In general, POAG patients demonstrated lower ACh% and AChmax values compared with controls. There was significant difference in microvascular endothelial function [ACh%: mean, 95% confidence interval = 503.1 (378.0, 628.3), and AChmax: mean, 95% confidence interval = 36.8 (30.2, 43.5)] between primary open angle glaucoma cases (p 

    Matched MeSH terms: Nitroprusside
  20. Mohd Amnan MA, Pua TL, Lau SE, Tan BC, Yamaguchi H, Hitachi K, et al.
    PeerJ, 2021;9:e10879.
    PMID: 33614294 DOI: 10.7717/peerj.10879
    Drought is one of the severe environmental stresses threatening agriculture around the globe. Nitric oxide plays diverse roles in plant growth and defensive responses. Despite a few studies supporting the role of nitric oxide in plants under drought responses, little is known about its pivotal molecular amendment in the regulation of stress signaling. In this study, a label-free nano-liquid chromatography-mass spectrometry approach was used to determine the effects of sodium nitroprusside (SNP) on polyethylene glycol (PEG)-induced osmotic stress in banana roots. Plant treatment with SNP improved plant growth and reduced the percentage of yellow leaves. A total of 30 and 90 proteins were differentially identified in PEG+SNP against PEG and PEG+SNP against the control, respectively. The majority of proteins differing between them were related to carbohydrate and energy metabolisms. Antioxidant enzyme activities, such as superoxide dismutase and ascorbate peroxidase, decreased in SNP-treated banana roots compared to PEG-treated banana. These results suggest that the nitric oxide-induced osmotic stress tolerance could be associated with improved carbohydrate and energy metabolism capability in higher plants.
    Matched MeSH terms: Nitroprusside
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