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Palm oil tocotrienol fractions restore endothelium dependent relaxation in aortic rings of streptozotocin-induced diabetic and spontaneously hypertensive rats

Muharis SP, Top AG, Murugan D, Mustafa MR

Nutr Res, 2010 Mar;30(3):209-16.
PMID: 20417882 DOI: 10.1016/j.nutres.2010.03.005

Diabetes and hypertension are closely associated with impaired endothelial function. Studies have demonstrated that regular consumption of edible palm oil may reverse endothelial dysfunction. The present study investigates the effect of palm oil fractions: tocotrienol rich fraction (TRF), alpha-tocopherol and refined palm olein (vitamin E-free fraction) on the vascular relaxation responses in the aortic rings of streptozotocin-induced diabetic and spontaneously hypertensive rats (SHR). We hypothesize that the TRF and alpha-tocopherol fractions are able to improve endothelial function in both diabetic and hypertensive rat aortic tissue. A 1,1-diphenyl picryl hydrazyl assay was performed on the various palm oil fractions to evaluate their antioxidant activities. Endothelium-dependent (acetylcholine) and endothelium-independent (sodium nitroprusside) relaxations were examined on streptozotocin-induced diabetic and SHR rat aorta following preincubation with the different fractions. In 1-diphenyl picryl hydrazyl antioxidant assay, TRF and alpha-tocopherol fractions exhibited a similar degree of activity while palm olein exhibited poor activity. TRF and alpha-tocopherol significantly improved acetylcholine-induced relaxations in both diabetic (TRF, 88.5% +/- 4.5%; alpha-tocopherol, 87.4% +/- 3.4%; vehicle, 65.0 +/- 1.6%) and SHR aorta (TRF, 72.1% +/- 7.9%; alpha-tocopherol, 69.8% +/- 4.0%, vehicle, 51.1% +/- 4.7%), while palm olein exhibited no observable effect. These results suggest that TRF and alpha-tocopherol fractions possess potent antioxidant activities and provide further support to the cardiovascular protective effects of palm oil vitamin E. TRF and alpha-tocopherol may potentially improve vascular endothelial function in diabetes and hypertension by their sparing effect on endothelium derived nitric oxide bioavailability.

Matched MeSH terms: Muscle, Smooth, Vascular/physiopathology
Cardiovascular activity of the n-butanol fraction of the methanol extract of Loranthus ferrugineus Roxb

Ameer OZ, Salman IM, Siddiqui MJ, Yam MF, Sriramaneni RN, Sadikun A, et al.

Braz. J. Med. Biol. Res., 2010 Feb;43(2):186-94.
PMID: 20084331

We investigated the vascular responses and the blood pressure reducing effects of different fractions obtained from the methanol extract of Loranthus ferrugineus Roxb. (F. Loranthaceae). By means of solvent-solvent extraction, L. ferrugineus methanol extract (LFME) was successively fractionated with chloroform, ethyl acetate and n-butanol. The ability of these LFME fractions to relax vascular smooth muscle against phenylephrine (PE)- and KCl-induced contractions in isolated rat aortic rings was determined. In another set of experiments, LFME fractions were tested for blood pressure lowering activity in anesthetized adult male Sprague-Dawley rats (250-300 g, 14-18 weeks). The n-butanol fraction of LFME (NBF-LFME) produced a significant concentration-dependent inhibition of PE- and KCl-induced aortic ring contractions compared to other fractions. Moreover, NBF-LFME had a significantly higher relaxant effect against PE- than against high K+-induced contractions. In anesthetized Sprague-Dawley rats, NBF-LFME significantly lowered blood pressure in a dose-dependent manner and with a relatively longer duration of action compared to the other fractions. HPLC, UV and IR spectra suggested the presence of terpenoid constituents in both LFME and NBF-LFME. Accordingly, we conclude that NBF-LFME is the most potent fraction producing a concentration-dependent relaxation in vascular smooth muscle in vitro and a dose-dependent blood pressure lowering activity in vivo. The cardiovascular effects of NBF-LFME are most likely attributable to its terpenoid content.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects*
Fulltext Myoid hamartoma of breast with chondroid metaplasia: a case report

Khoo JJ, Alwi RI, Abd-Rahman I

Malays J Pathol, 2009 Jun;31(1):77-80.
PMID: 19694319 MyJurnal

Breast hamartoma is an uncommon poorly recognised benign breast neoplasm. Hamartoma displaying marked smooth muscle components known as myoid hamartoma of the breast is a much rarer entity. We present a case of myoid hamartoma of breast with chondroid differentiation in a 46-year-old woman. The painless breast lump was circumscribed and mammography showed a well-encapsulated large, dense mass with no calcification. Core needle biopsy was reported as fibroadenoma. The lesion was excised. Microscopically, it composed of many groups of mammary glandular components with dense fibrous stroma, adipose tissue and marked groups of smooth muscle fibres. Foci of chondroid differentiation were noted in the lesion. The smooth muscle cells showed strong and diffuse immunoreactivity for vimentin, myogloblin, alpha-smooth muscle actin, desmin and CD34 and failed to express pan-cytokeratin or S100 protein. The ducts lined by epithelial cells were reactive to pan-cytokeratin while the myoepithelial cells were reactive to S100 protein. The various immuno-histochemical staining as well as the cyto-histological changes encountered in myoid hamartomas are discussed with clinical, radiological and pathological correlation to differentiate it from other benign and malignant breast lesions.

Matched MeSH terms: Muscle, Smooth/metabolism; Muscle, Smooth/pathology*
Effect of alpha lipoic acid on oxidative stress and vascular wall of diabetic rats

Balkis Budin S, Othman F, Louis SR, Abu Bakar M, Radzi M, Osman K, et al.

Rom J Morphol Embryol, 2009;50(1):23-30.
PMID: 19221642

PREMISES AND OBJECTIVES: Antioxidant plays an important role in preventing the progression of diabetes mellitus (DM) complications. The aim of the present study was to investigate the effect of alpha lipoic acid (ALA) supplementation on plasma lipid, oxidative stress and vascular changes in diabetic rats.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects; Muscle, Smooth, Vascular/pathology; Muscle, Smooth, Vascular/physiopathology*; Muscle, Smooth, Vascular/ultrastructure
Fulltext Renal angiomyolipomas in the University of Malaya Medical Centre: its spectrum of presentation and management

Koh, P.S., Muhilan, P., Dublin, N., Razack, A.H.

JUMMEC, 2009;12(1):39-43.
MyJurnal

Renal angiomyolipoma, once considered a rare benign renal tumour, is relatively common these days. They account for 0.3-3.0% of all renal masses. Histologically, it is composed of adipose tissue, smooth muscles and blood vessels. Here, we wish to highlight five cases of renal angiomyolipomas which were presented to the University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia, over a two-year period between June 2005 and June 2007. This study wish to illustrate its varied clinical presentation and the management undertaken for each underlying condition. These cases were presented in the form of spontaneous perirenal haemorrhage, a large asymptomatic renal mass, a small asymptomatic renal mass, a symptomatic renal angiomyolipoma and a case of renal angiomyolipoma mimicking a renal tumour. Each of these cases varied in its clinical presentation; thus, management has become very challenging to clinicians ranging from conservative management to active intervention, be it operatively or non-operatively.

Matched MeSH terms: Muscle, Smooth
The effects of palm oil tocotrienol-rich fraction supplementation on biochemical parameters, oxidative stress and the vascular wall of streptozotocin-induced diabetic rats

Budin SB, Othman F, Louis SR, Bakar MA, Das S, Mohamed J

Clinics (Sao Paulo), 2009;64(3):235-44.
PMID: 19330251

OBJECTIVE: This study examined the effects of palm oil tocotrienol-rich fractions on streptozotocin-induced diabetic rats.
METHODS: Animals were divided into three groups: (i) normal non-diabetic (NDM), (ii) diabetic treated (tocotrienol-rich fractions - TRF) and (iii) diabetic untreated (non-TRF). The treatment group received oral administration of tocotrienol-rich fractions (200 mg/kg body weight) daily for eight weeks. The normal non-diabetic and the diabetic untreated groups were fed standard rat feed. Blood glucose and lipid profiles, oxidative stress markers and morphological changes of the thoracic aorta were evaluated.
RESULTS: Tocotrienol-rich fractions treatment reduced serum glucose and glycated hemoglobin concentrations. The tocotrienol-rich fractions group also showed significantly lower levels of plasma total cholesterol, low-density lipoprotein cholesterol, and triglyceride, as compared to the untreated group. The tocotrienol-rich fractions group had higher levels of high-density lipoprotein cholesterol, as compared to the untreated group. Superoxide dismutase activity and levels of vitamin C in plasma were increased in tocotrienol-rich fractions-treated rats. The levels of plasma and aorta malondealdehyde + 4-hydroxynonenal (MDA + 4-HNE) and oxidative DNA damage were significant following tocotrienol-rich fractions treatment. Electron microscopic examination showed that the normal morphology of the thoracic aorta was disrupted in STZ-diabetic rats. Tocotrienol-rich fractions supplementation resulted in a protective effect on the vessel wall.
CONCLUSION: These results show that tocotrienol-rich fractions lowers the blood glucose level and improves dyslipidemia. Levels of oxidative stress markers were also reduced by administration of tocotrienol-rich fractions. Vessel wall integrity was maintained due to the positive effects mediated by tocotrienol-rich fractions.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects; Muscle, Smooth, Vascular/ultrastructure
Modulation of vascular reactivity in normal, hypertensive and diabetic rat aortae by a non-antioxidant flavonoid

Ajay M, Achike FI, Mustafa MR

Pharmacol Res, 2007 May;55(5):385-91.
PMID: 17317209

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 (10 microM) 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 alpha(1)-receptor agonist phenylephrine (PE) in WKY aortae compared to those observed in control aortic rings. Flavone had no effect on relaxations to ACh in WKY aortae incubated with either L-NAME or methylene blue, but enhanced relaxations to ACh in WKY aortae incubated with indomethacin or partially depolarized with KCl. Relaxations to ACh are totally abolished in both control or flavone pretreated endothelium-denuded WKY aortae. Flavone attenuated the inhibition by beta-NADH of ACh-induced relaxation in WKY aortae, but it had no significant effect on the transient contractions induced by beta-NADH nor the pyrogallol-induced abolishment of ACh-induced relaxation in WKY aortae. Flavone enhanced endothelium-independent relaxation to sodium nitroprusside (SNP) in both endothelium-intact and -denuded WKY aortae. Flavone enhanced relaxation to ACh and SNP as well as attenuated contractile effects to PE in SHR and diabetic aortae, a finding similar to that observed in normal WKY aortae. From these results, we conclude that flavone modulates vascular reactivity in normal as well as hypertensive and diabetic aortae. These effects of flavone results probably through enhanced bioactivity of nitric oxide released from the endothelium.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects; Muscle, Smooth, Vascular/physiopathology
Direct effects of quercetin on impaired reactivity of spontaneously hypertensive rat aortae: comparative study with ascorbic acid

Ajay M, Achike FI, Mustafa AM, Mustafa MR

Clin Exp Pharmacol Physiol, 2006 Apr;33(4):345-50.
PMID: 16620299

1. There is a growing interest in the anti-oxidant characteristics and use of flavonoids in the management of cardiovascular diseases. The cardiovascular mechanism of action of these plant derivatives remains controversial. This study compared the effects of the flavonoid quercetin with those of the anti-oxidant vitamin ascorbic acid (vitamin C) on the reactivity of aortic rings from spontaneously hypertensive rats (SHR). 2. The phenylephrine (PE)-induced contractile and the endothelium-dependent and independent relaxant responses of aortic rings from 21 to 22 week old SHR and age-matched normotensive Wistar (WKY) rats were observed in the presence of quercetin or ascorbic acid. All the experiments were performed in the presence of the cyclooxygenase inhibitor, indomethacin (10 micromol/L). 3. The endothelium-dependent and independent relaxations to acetylcholine (ACh) and sodium nitroprusside (SNP), respectively, were significantly lesser in the SHR compared to the WKY tissues whereas the contractile responses to PE were similar in both tissues. Pretreatment of WKY rings with quercetin or ascorbic acid had no effect on the responses to ACh or PE. In the SHR tissues, however, quercetin or ascorbic acid significantly improved the relaxation responses to ACh and reduced the contractions to PE with greater potency for quercetin. Both compounds lacked any effects on the responses to SNP in either aortic ring types. N(omega)-nitro-L-arginine methyl ester (l-NAME, 10 micromol/L) significantly attenuated the vasodepressor effects of quercetin and ascorbic acid, raising the responses to PE to a level similar to that observed in the control SHR tissues. In l-NAME pretreated aortic rings, quercetin and ascorbic acid inhibited the contractile responses to PE with the same magnitude in WKY and SHR tissues. 4. The present results suggest that acute exposure to quercetin improves endothelium-dependent relaxation and reduces the contractile responses of hypertensive aortae with a greater potency than ascorbic acid. This suggests a better vascular protection with this flavonoid than ascorbic acid in the SHR model of hypertension and possibly in human cardiovascular diseases.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects
Goniothalamin induces apoptosis in vascular smooth muscle cells

Chan KM, Rajab NF, Ishak MH, Ali AM, Yusoff K, Din LB, et al.

Chem Biol Interact, 2006 Feb 1;159(2):129-40.
PMID: 16297902

Restenosis represents a major impediment to the success of coronary angioplasty. Abnormal proliferation of vascular smooth muscle cells (VSMCs) has been shown to be an important process in the pathogenesis of restenosis. A number of agents, particularly rapamycin and paclitaxel, have been shown to impact on this process. This study was carried out to determine the mechanisms of cytotoxicity of goniothalamin (GN) on VSMCs. Results from MTT cytotoxicity assay showed that the IC(50) for GN was 4.4 microg/ml (22 microM), which was lower compared to the clinically used rapamycin (IC(50) of 25 microg/ml [27.346 microM]). This was achieved primarily via apoptosis where up to 25.83 +/- 0.44% of apoptotic cells were detected after 72 h treatment with GN. In addition, GN demonstrated similar effects as rapamycin in inhibiting VSMCs proliferation using bromodeoxyuridine (BrdU) cell proliferation assay after 72 h treatment at IC(50) concentration (p > 0.05). In order to understand the mechanisms of GN, DNA damage detection using comet assay was determined at 2h post-treatment with GN. Our results showed that there was a concentration-dependent increase in DNA damage in VSMCs prior to cytotoxicity. Moreover, GN effects were comparable to rapamycin. In conclusion, our data show that GN initially induces DNA damage which subsequently leads to cytotoxicity primarily via apoptosis in VSMCs.

Matched MeSH terms: Muscle, Smooth, Vascular/cytology; Muscle, Smooth, Vascular/drug effects*
Presence of calcium antagonist activity explains the use of Syzygium samarangense in diarrhoea

Ghayur MN, Gilani AH, Khan A, Amor EC, Villaseñor IM, Choudhary MI

Phytother Res, 2006 Jan;20(1):49-52.
PMID: 16397921

Syzygium samarangense (Family; Myrtaceae) or 'makopa', as it is commonly known, is native to Malaysia, some islands of Indonesia and to Far East in general. This study was undertaken to rationalize the use of this plant in hypermotility states of the gut. The hexane extract of S. samarangense (Ss.Hex) was found to dose-dependently (10-3000 microg/mL) relax the spontaneously contracting isolated rabbit jejunum. When tested for a possible calcium channel blocking (CCB) activity, the extract (10-1000 microg/mL) relaxed the high K+-induced contractions and also decreased the Ca++ dose-response curves in a dose-dependent manner (30-100 microg/mL), confirming the CCB activity. Four flavonoids isolated from the hexane extract were tested for a possible spasmolytic activity. All flavonoids, identified as: 2'-hydroxy-4',6'-dimethoxy-3'-methylchalcone (SS1), 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (SS2), 2',4'-dihydroxy-6'-methoxy-3'-methylchalcone (SS3) and 7-hydroxy-5-methoxy-6,8-dimethylflavanone (SS4), showed dose-dependent (10-1000 microg/mL) spasmolytic activity with SS2 being the most potent. These results indicate that the presence of compounds with spasmolytic and calcium antagonist activity may be responsible for the medicinal use of the plant in diarrhoea.

Matched MeSH terms: Muscle, Smooth/drug effects
Fulltext A case of lymphangioleiomyomatosis with multiple angiomyolipomas in the kidneys: a case report

How, S.H., Azlin, S., Pang, Y.K., Liam, C.K.

JUMMEC, 2006;9(2):35-38.
MyJurnal

Lymphangioleiomyomatosis (LAM) is a rare disease. The reported prevalence is around one per million in the West but the exact prevalence in Asia is unknown. It affects primarily young women of reproductive age, with a mean age of onset at 34 years. The disease is characterised by an abnormal proliferation of smooth muscle-like cells that grow over a course of time to obstruct airways, lymphatic and blood vessels. We report a case of LAM in a young woman who presented with a spontaneous pneumothorax. Computed tomography scan of the thorax and abdomen showed homogenous thin-walled cystic lesions with normal intervening lung parenchyma and multiple lesions in her kidneys with Hounsfield units similar to that of fat.

Matched MeSH terms: Muscle, Smooth
Fulltext A clinical and immunohistochemical study of gastrointestinal stromal tumours

Khoo JJ, Gunn A

Malays J Pathol, 2005 Jun;27(1):9-16.
PMID: 16676687

AIM: To study the clinical features, histology and immunohistochemical properties of gastrointestinal stromal tumours (GISTs); and establish any parameters that can help prognosticate the malignant potential.
METHODS: Twenty-six patients with GISTs who were seen in Sultanah Aminah Hospital Johor, Malaysia from 1999 to 2003 were selected for study. Patient, clinical characteristics and outcome based on surgical records were analysed. Tumour variables (tumour size, cellularity, mitotic count, necrosis and haemorrhage) were compared between very low to low risk groups and intermediate to high risk groups. The immunohistochemical properties of GISTs were also studied.
RESULTS: Patients with GISTs presented mainly with pain, palpable mass or gastrointestinal tract bleeding. The tumours were seen in stomach (50%) followed by small intestine (38.5%) and rectum (11.5%). In the period of study, six patients had metastasis, mainly in the liver or peritoneum. Immunoreactivity for CD117, CD34, vimentin, S100, neuron specific enolase, alpha-smooth-muscle-actin and desmin were observed in 100%, 76.9%, 61.5%, 46.1%, 80.8%, 11.5% and 0% of tumours respectively. The behaviour of GISTs was largely dependent on tumour size and number of mitosis. Necrosis and haemorrhage were seen in tumours with high risk potential.

Matched MeSH terms: Muscle, Smooth/metabolism
Fulltext Changing paradigms in the treatment of asthma

Loh LC

Family Physician, 2005;13(3):0-0.
MyJurnal

Significant changes have occurred in relation to how chronic asthma is being treated. Emphasis has now shifted from viewing asthma as a condition of smooth muscle dysfunction to one of chronic inflammation. As such, anti-inflammatory therapy forming the cornerstone of treatment represents the first important milestone in the evolution of asthma treatment. For this purpose, inhaled corticosteroid (ICS) is by far the most effective anti-inflammatory therapy. Another important milestone is the recognition of the superiority of adding long-acting β2-agonist (LABA) to ICS over escalating ICS dose alone or other forms of add-on therapies in treating asthmatic patients not responding to regular ICS alone. The effectiveness of adding LABA to ICS in treating asthma logically led to combining the two drugs into one single inhaler (salmeterol/fluticasone and budesonide/formoterol) that has the attractiveness of being user-friendly and ensuring that ICS is not missed out. The unique property of formoterol that allows for repetitive flexible dosing paved way to the concept of using Symbicort for both regular maintenance dosing and as required rescue medication. This revolutionary approach has been recently shown to provide improved asthma outcome, achieved at an overall lower or at least comparable corticosteroid intake, and may represent another evolutionary step in the treatment strategy of chronic asthma.

Matched MeSH terms: Muscle, Smooth
The contribution of adrenoceptor subtype(s) in the renal vasculature of diabetic spontaneously hypertensive rats

Armenia A, Munavvar AS, Abdullah NA, Helmi A, Johns EJ

Br J Pharmacol, 2004 Jun;142(4):719-26.
PMID: 15172958

1. Diabetes and hypertension are both associated with an increased risk of renal disease and are associated with neuropathies, which can cause defective autonomic control of major organs including the kidney. This study aimed to examine the alpha(1)-adrenoceptor subtype(s) involved in mediating adrenergically induced renal vasoconstriction in a rat model of diabetes and hypertension. 2. Male spontaneously hypertensive rats (SHR), 220-280 g, were anaesthetized with sodium pentobarbitone 7-day poststreptozotocin (55 mg x kg(-1) i.p.) treatment. The reductions in renal blood flow (RBF) induced by increasing frequencies of electrical renal nerve stimulation (RNS), close intrarenal bolus doses of noradrenaline (NA), phenylephrine (PE) or methoxamine were determined before and after administration of nitrendipine (Nit), 5-methylurapidil (5-MeU), chloroethylclonidine (CEC) and BMY 7378. 3. In the nondiabetic SHR group, mean arterial pressure (MAP) was 146+/-6 mmHg, RBF was 28.0+/-1.4 ml x min(-1) x kg(-1) and blood glucose was 112.3+/-4.7 mg x dl(-1), and in the diabetic SHR Group, MAP was 144+/-3 mmHg, RBF 26.9+/-1.3 ml(-1) min x kg(-1) and blood glucose 316.2+/-10.5 mg x dl(-1). Nit, 5-MeU and BMY 7378 blunted all the adrenergically induced renal vasoconstrictor responses in SHR and diabetic SHR by 25-35% (all P<0.05), but in diabetic rats the responses induced by RNS and NA treated with 5-MeU were not changed. By contrast, during the administration of CEC, vasoconstrictor responses to all agonists were enhanced by 20-25% (all P<0.05) in both the SHR and diabetic SHR. 4. These findings suggest that alpha(1A) and alpha(1D)-adrenoceptor subtypes contribute in mediating the adrenergically induced constriction of the renal vasculature in both the SHR and diabetic SHR. There was also an indication of a greater contribution of presynaptic adrenoceptors, that is, alpha(1B)-, and/or alpha(2)-subtypes.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects; Muscle, Smooth, Vascular/physiopathology
Factors inducing in-stent restenosis: an in-vitro model

Santin M, Morris C, Harrison M, Mikhalovska L, Lloyd AW, Mikhalovsky S

Med J Malaysia, 2004 May;59 Suppl B:93-4.
PMID: 15468834

In-stent restenosis is caused by the proliferation of the smooth muscle cells (SMCs) following a host response towards the implanted device. However, the precise biochemical and cellular mechanisms are still not completely understood. In this paper, the behaviour of SMCs has been investigated by an in vitro model where the cells were stimulated by platelet derived growth factor (PDGF) on tissue-like substrates as well as on biomaterials such as stainless steel (St) and diamond-like carbon (DLC)-coated St. The results demonstrated that SMCs have a completely different adhesion mode on St and become particularly prone to proliferation and pro-inflammatory cytokine secretion under PDGF stimulus. This would suggest that restenosis may caused by the accidental contact of the SMC with the St substrate under an inflammatory insult.

Matched MeSH terms: Muscle, Smooth, Vascular/physiopathology*
Effects of flavonoids on vascular smooth muscle of the isolated rat thoracic aorta

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: Muscle, Smooth, Vascular/drug effects*
Characterization of a novel tetrandrine-induced contraction in rat tail artery

Achike FI, Kwan CY

Acta Pharmacol Sin, 2002 Aug;23(8):698-704.
PMID: 12147191

In an attempt to pharmacologically characterize the Chinese antihypertensive drug, tetrandrine, we observed in rat-tail arteries, an unusual contraction in tissues that were stimulated with high [KCl] and not those stimulated with phenylephrine. The characteristics of this contraction were studied.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects*; Muscle, Smooth, Vascular/physiology
Dicentrine is preferentially antagonistic to rat aortic than splenic alpha 1-adrenoceptor stimulation

Mustafa MR, Achike FI

Acta Pharmacol Sin, 2000 Dec;21(12):1165-8.
PMID: 11603294

Dicentrine is a known alpha 1-adrenoceptor antagonist, but its alpha 1-adrenoceptor subtype selectivity has not yet been determined. We therefore, investigated the putative alpha 1-adrenoceptor subtype selectivity of this agent.

Matched MeSH terms: Muscle, Smooth/drug effects; Muscle, Smooth, Vascular/drug effects
New therapies for erectile dysfunction

Tan HM

Int. J. Androl., 2000;23 Suppl 2:87-8.
PMID: 10849506

The quest for improving and maintaining sexual function has been going on since time immemorial. The advent of an effective oral drug, sildenafil, has brought about unprecedented open discussion on male erectile dysfunction, and gas accelerated the pace of development of new therapies for erectile dysfunction. New knowledge in the physiology of sexual function has enabled researchers to target drug treatment at the whole network of the central nervous system and the numerous cascadic enzymatic reactions leading to relaxation of the corporal smooth muscle. One of the brightest potential applications of future molecular technology in the study of erectile dysfuction is in the utilization of gene therapy.

Matched MeSH terms: Muscle, Smooth, Vascular/drug effects; Muscle, Smooth, Vascular/physiopathology
Incidence of acute atherosis in complete molar pregnancy

Hayati AR, Azizah A, Wahidah A

Malays J Pathol, 1998 Dec;20(2):113-4.
PMID: 10879273

A clinicohistological study of acute atherosis in molar pregnancy was undertaken. Maternal decidual vessels in currettage samples of 38 histologically confirmed complete hydatidiform moles were examined histologically for acute atherosis, recognised as fibrinoid necrosis of the smooth muscle wall with a perivascular mononuclear cell infiltrate, with or without lipophages. Acute atherosis was detected in eight of 38 cases, an incidence of 18.4%. All the patients were normotensive. The significance of acute atherosis in molar pregnancy remains to be clarified.

Matched MeSH terms: Muscle, Smooth, Vascular/pathology

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