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Full-Text Articles in Pharmacology

Effects Of Angiotensin 1-7 On The Actions Of Angiotensin Ii In The Renal And Mesenteric Vasculature Of Hypertensive And Streptozotocin-Induced Diabetic Rats, Mohd Rais Mustafa, Murugan Dharmani, Francis I. Achike, Meng-Kwoon Sim Apr 2007

Effects Of Angiotensin 1-7 On The Actions Of Angiotensin Ii In The Renal And Mesenteric Vasculature Of Hypertensive And Streptozotocin-Induced Diabetic Rats, Mohd Rais Mustafa, Murugan Dharmani, Francis I. Achike, Meng-Kwoon Sim

Mohd Rais Mustafa

Angiotensin 1-7, a heptapeptide derived from metabolism of either angiotensin I or angiotensin II, is a biologically active peptide of the renin–angiotensin system. The present study investigated the effect of angiotensin 1-7 on the vasopressor action of angiotensin II in the renal and mesenteric vasculature of Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHR) and streptozotocin-induced diabetic rats. Angiotensin II-induced dose-dependent vasoconstrictions in the renal vasculature. The pressor response was enhanced in the SHR and reduced in the streptozotocin-diabetic rat compared to WKY rats. Angiotensin 1-7 attenuated the angiotensin II pressor responses in the renal vasculature of WKY and SHR rats. …


Modulation Of Vascular Reactivity In Normal, Hypertensive And Diabetic Rat Aortae By A Non-Antioxidant Flavonoid, Mohd Rais Mustafa, Macha Ajay, Fracis I. Achike Jan 2007

Modulation Of Vascular Reactivity In Normal, Hypertensive And Diabetic Rat Aortae By A Non-Antioxidant Flavonoid, Mohd Rais Mustafa, Macha Ajay, Fracis I. Achike

Mohd Rais Mustafa

In this study, we report the effects of a non-antioxidant flavonoid flavone on vascular reactivity in Wistar–Kyoto (WKY) rat isolated aortae. Whether flavone directly modulates vascular reactivity in spontaneously hypertensive rat (SHR) and streptozotocin-induced diabetic-WKY rat isolated aortae was also determined. Thoracic aortic rings were mounted in organ chambers and exposed to various drug treatments in the presence of flavone or its vehicle (DMSO), which served as control. Pretreatment with flavone enhanced relaxant effects to endothelium-dependent vasodilator acetylcholine (ACh) and attenuated contractile effects to 1-receptor agonist phenylephrine (PE) in WKY aortae compared to those observed in control aortic rings. Flavone …


Effects Of Ascorbic Acid On Impaired Vascular Reactivity In Aortas Isolated From Age-Matched Hypertensive And Diabetic Rats, Mohd Rais Mustafa, Macha Ajay Jan 2006

Effects Of Ascorbic Acid On Impaired Vascular Reactivity In Aortas Isolated From Age-Matched Hypertensive And Diabetic Rats, Mohd Rais Mustafa, Macha Ajay

Mohd Rais Mustafa

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 …


Bioassay-Guided Isolation Of A Vasorelaxant Active Compound From Kaempferia Galanga L, Mohd Rais Mustafa, Khalijah Awang, Mustafa Ali Mohd, Rozana Othman, Halijah Ibrahim Jan 2006

Bioassay-Guided Isolation Of A Vasorelaxant Active Compound From Kaempferia Galanga L, Mohd Rais Mustafa, Khalijah Awang, Mustafa Ali Mohd, Rozana Othman, Halijah Ibrahim

Mohd Rais Mustafa

Bioassay-guided fractionation was performed on a crude dichloromethane extract of Kaempferia galanga L. using chromatography techniques. Screening of the extract for biological activity started with the brine shrimp lethality bioassay, followed by the study of its antihypertensive activity on anaesthetized rats, which involved monitoring of the extract's effect on mean arterial blood pressure. The components of the fractions obtained from the separation procedures were analyzed using gas chromatography (GC). The yield of the CH2Cl2 extract was 0.29% of the crude plant extract. Analysis of the data for brine shrimp lethality test using the Finney computer program showed that this extract …


Effects Of Des-Aspartate-Angiotensin I On The Actions Of Angiotensin Iii In The Renal And Mesenteric Vasculature Of Normo-And Hypertensive Rats, Mohd Rais Mustafa, Murugan Dharmani, Kunheen N.K, Meng-Kwoon Sim Aug 2004

Effects Of Des-Aspartate-Angiotensin I On The Actions Of Angiotensin Iii In The Renal And Mesenteric Vasculature Of Normo-And Hypertensive Rats, Mohd Rais Mustafa, Murugan Dharmani, Kunheen N.K, Meng-Kwoon Sim

Mohd Rais Mustafa

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 dosedependent 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 …


Vasorelaxant Effects Of Ethyl Cinnamate Isolated From Kaempferia Galanga On Smooth Muscles Of The Rat Aorta, Mohd Rais Mustafa, Rozana Othman, Halijah Ibrahim, Mustafa Ali Mohd, Khalijah Awang, Anwar-Ul Hassan Gilani Jan 2001

Vasorelaxant Effects Of Ethyl Cinnamate Isolated From Kaempferia Galanga On Smooth Muscles Of The Rat Aorta, Mohd Rais Mustafa, Rozana Othman, Halijah Ibrahim, Mustafa Ali Mohd, Khalijah Awang, Anwar-Ul Hassan Gilani

Mohd Rais Mustafa

From the rhizomes of Kaempferia galanga, ethyl cinnamate (EC) was isolated and its vasorelaxant effect was examined on the rat aorta. EC inhibited the tonic contractions induced by high K+ and phenylephrine (PE) in a concentration-dependent manner, with respective IC50 values of 0.30 ± 0.05 mM and 0.38 ± 0.04 mM. The relaxant effect against PE-induced contractions was greater in the presence of endothelium. Pre-treatment of the aorta with methylene blue and indomethacin significantly reduced the relaxant effect. These results suggest that the inhibitory effects of EC may involve inhibition of Ca2+ influx into vascular cells and release of nitric …


Oscillations And Waves Of Intracellular [Ca2+] In Cardiac-Muscle-Cells, Mohd Rais Mustafa Jan 1995

Oscillations And Waves Of Intracellular [Ca2+] In Cardiac-Muscle-Cells, Mohd Rais Mustafa

Mohd Rais Mustafa

When cardiac muscle cells become overloaded with Ca2+, spontaneous releases of Ca2+ from the sarcoplasmic reticulum can occur. Such spontaneous releases normally originate within a localized region of the cell and propagate as a wave throughout the cell. The amplitude and frequency of these Ca2+ releases increase with the degree of Ca2+ loading of the cell, and are abolished by interventions which inhibit sarcoplasmic reticulum function. It is still not clear whether these releases are triggered by a rise in the [Ca2+] in the lumen of the sarcoplasmic reticulum or by a rise in cytoplasmic [Ca2+]. Such releases may, however, …