MyMedR

Displaying publications 41 - 60 of 84 in total

Abstract:

Sort:

The effects of propranolol on skeletal muscle contraction, lipid peroxidation products and antioxidant activity in experimental hyperthyroidism

Zaiton Z, Merican Z, Khalid BA, Mohamed JB, Baharom S

Gen. Pharmacol., 1993 Jan;24(1):195-9.
PMID: 8482496

1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.

Matched MeSH terms: Muscle Contraction/drug effects*
Inhibition of gastrointestinal release of acetylcholine by quercetin as a possible mode of action of Psidium guajava leaf extracts in the treatment of acute diarrhoeal disease

Lutterodt GD

J Ethnopharmacol, 1989 May;25(3):235-47.
PMID: 2747259

The electrically stimulated guinea-pig ileum and spontaneously contracting guinea-pig ileum preparations were employed in studies on the effects of an alcoholic extract and two flavonoid compounds, quercetin and quercetin-3-arabinoside, extracted from the leaves of Psidium guajava. The extract showed a morphine-like inhibition of acetylcholine release in the coaxially stimulated ileum, together with an initial increase in muscular tone, followed by a gradual decrease. The morphine-like inhibition was found to be due to quercetin, starting at concentrations of 1.6 micrograms/ml. The glycoside did not show any such action at concentrations of up to 1.28 mg/ml. The extract inhibited spontaneous contractions in the unstimulated ileum with a concentration-response relationship.

Matched MeSH terms: Muscle Contraction/drug effects
Studies on the Indonesian Antiaris toxicaria sap

Fujimoto Y, Suzuki Y, Kanaiwa T, Amiya T, Hoshi K, Fujino S

J. Pharmacobio-dyn., 1983 Feb;6(2):128-35.
PMID: 6306201

The present research is on a milky sap obtained from the Antiaris toxicaria tree (Moraceae) which is called Upas or Ipoh in Indonesia. The crude sap was administered to anesthetized rats, and changes in electrocardiogram (ECG) and systemic blood pressure was observed. Biologically and pharmacologically active components were extracted from the crude sap by means of water-acetone solution. Based on the strength of chemical qualitative detection tests of the sap extract (SE), cardiac glycosides are supposed to be the main components. The SE inhibited the Na+-, K+-ATPase (EC 3.6.1.3) which was partially purified from guinea pig heart muscle. When the SE and, concurrently, authentic ouabain were applied to isolated frog heart muscles, the fall of twitch tension was observed after the increased tension on mechanograms. These facts suggest that the main components of the milky sap are cardiac glycosides, and glycosides affect Na+, K+-ATPase activity of muscle membrane and heart muscle contraction.

Matched MeSH terms: Muscle Contraction/drug effects
In vitro differentiation of mesenchymal stem cells into mesangial cells when co-cultured with injured mesangial cells

Wong CY, Tan EL, Cheong SK

Cell Biol Int, 2014 Apr;38(4):497-501.
PMID: 24375917 DOI: 10.1002/cbin.10231

Mesangial cells are one of the three major cell types of the kidney glomerulus that provide physical support for the glomerular capillary lumen of the kidney. Loss of mesangial cells due to pathologic conditions, such as glomerulonephritis and diabetic nephropathy, can impair renal function. Mesenchymal stem cells (MSC) are attractive candidates for kidney repair therapy since they can enhance recovery and protect against kidney failure. MSC can differentiate into mesangial cells in vivo. We have investigated the ability of MSC to differentiate into mesangial cells in vitro; they were co-cultured with oxidant-injured mesangial cells before being analysed by flow cytometry and for contractility. MSC co-cultured with injured mesangial cells had a mesangial cell-like morphology and contracted in response to angiotensin II. They expressed CD54(-) CD62E(+) in direct contrast to the CD54(+) CD62E(-) of pure MSC. In conclusion, MSC can differentiate into mesangial cells in vitro when co-cultured with injured mesangial cells.

Matched MeSH terms: Muscle Contraction/drug effects
Inhibition of calcium-dependent contractions of the isolated guinea-pig ileal longitudinal muscle and taenia coli by the total glycosidic extract of the plant Sarcolobus globosus

Mustafa MR

Toxicon, 1993 Jan;31(1):67-74.
PMID: 8446965

The effect of the total glysosidic extract of the plant Sarcolobus globosus was investigated on the contractions of the smooth muscle of the guinea-pig ileal longitudinal muscle and taenia coli. In the ileal longitudinal muscle, addition of the extract inhibited the electrical field-stimulated twitches. Similarly to verapamil, it also reduced the contractions of the muscle to acetylcholine, histamine and KCl. However, only the tonic contraction to KCl was reversed by increasing the extracellular calcium concentration. In the taenia coli, lower concentrations of both the extract and verapamil induced a parallel displacement of the dose-response curves to calcium (0.30-30 mM). Addition of the extract also dose-dependently inhibited the KCl-induced contraction of the taenia coli. Increasing the calcium concentration increased the IC50 values of the extract. The result suggests that the inhibitory effect of the Sarcolobus globosus extract on the smooth muscle, like verapamil, is mainly due to inhibition of calcium influx.

Matched MeSH terms: Muscle Contraction/drug effects
The Association Between Levator-Urethra Gap Measurements and Symptoms and Signs of Female Pelvic Organ Prolapse

Kamisan Atan I, Shek KL, Furtado GI, Caudwell-Hall J, Dietz HP

Female Pelvic Med Reconstr Surg, 2016 Nov-Dec;22(6):442-446.
PMID: 27465815

OBJECTIVES: Levator avulsion is associated with pelvic organ prolapse in women. It is diagnosed clinically by a widened gap on palpation between the insertion of the puborectalis muscle on the inferior pubic ramus and the urethra. This gap can also be assessed on imaging. This study aimed to determine the association between sonographically determined levator-urethral gap (LUG) measurements and symptoms and signs of prolapse.

METHODS: This is a retrospective study on 450 women seen in a tertiary urogynecological center for symptoms of pelvic floor dysfunction between January 2013 and February 2014. All had a standardized interview, International Continence Society Pelvic Organ Prolapse Quantification assessment and 4-dimensional translabial ultrasound. Post-imaging analysis of archived ultrasound volumes for LUG measurement was undertaken on tomographic slices at the plane of minimal hiatal dimensions and within 5-mm cranial to this plane, bilaterally at an interslice interval of 2.5 mm, blinded against all clinical data. A LUG of 25 mm or greater was considered abnormal.

RESULTS: Mean LUG and maximum LUG in individuals were 22.5 mm (SD, 4.6) and 26.4 mm (SD, 6.0), respectively, with at least 1 abnormal LUG in 51% (n = 222). An abnormal LUG in all 3 slices involving the plane of minimal hiatal dimensions and within 5 mm cranial to this plane on at least 1 side was fulfilled in 24% (n = 103). The LUG measurements were strongly associated with bother, symptoms and signs of prolapse (P < 0.001 to 0.002). This remained significant on multivariate analysis controlling for potential confounding factors.

CONCLUSIONS: Sonographically determined LUG is strongly associated with symptoms, symptom bother, and pelvic organ prolapse on clinical examination and imaging.

Matched MeSH terms: Muscle Contraction/physiology
Differential Effects of 7 and 16 Groups of Muscle Relaxation Training Following Repeated Submaximal Intensity Exercise in Young Football Players

Sharifah Maimunah SM, Hashim HA

Percept Mot Skills, 2016 Feb;122(1):227-37.
PMID: 27420318 DOI: 10.1177/0031512515625383

This study compares two versions of progressive muscle relaxation (PMR) training (7 and 16 muscle groups) on oxygen consumption (VO2), heart rates, rating of perceived exertion and choice reaction time. Football (soccer) players (N = 26; M age = 13.4 yr., SD = 0.5) were randomly assigned to either 7 muscle groups PMR, 16 muscle groups PMR, or a control group. PMR training requires the participants to tense a muscle, hold the muscle contraction, and then relax it. Measurement was conducted prior to and after the completion of 12 sessions of PMR. The dependent variables were measured following four bouts of intermittent exercise consisting of 12 min. of running at 60% VO2max for 10 min. followed by running at 90% VO2max for 2 min. with a 3-min. rest for each bout. Lower VO2, heart rate, perceived exertion, and quicker reaction time were expected in both relaxation groups compared to the control group. The results revealed a significant reduction in heart rates and choice reaction time for both relaxation groups, but the longer version produced significantly quicker choice reaction time.

Matched MeSH terms: Muscle Contraction/physiology
Fulltext Effects of Root Extracts of Eurycoma longifolia Jack on Corpus Cavernosum of Rat

Tee BH, Hoe SZ, Cheah SH, Lam SK

Med Princ Pract, 2017;26(3):258-265.
PMID: 28226311 DOI: 10.1159/000464363

OBJECTIVE: This study was conducted to investigate the mechanisms of action of Eurycoma longifolia in rat corpus cavernosum.
MATERIALS AND METHODS: Tincture of the roots was concentrated to dryness by evaporating the ethanol in vacuo. This ethanolic extract was partitioned into 5 fractions sequentially with hexane, dichloromethane (DCM), ethyl acetate, butanol, and water. The corpus cavernosum relaxant activity of each fraction was investigated. The DCM fraction which showed the highest potency in relaxing phenylephrine-precontracted corpora cavernosa was purified by column chromatography. The effects of the most potent DCM subfraction in relaxing phenylephrine-precontracted corpora cavernosa, DCM-I, on angiotensin I- or angiotensin II-induced contractions in corpora cavernosa were investigated. The effects of DCM-I pretreatment on the responses of phenylephrine-precontracted corpora cavernosa to angiotensin II or bradykinin were also studied. An in vitro assay was conducted to evaluate the effect of DCM-I on angiotensin-converting enzyme activity.
RESULTS: Fraction DCM-I decreased the maximal contractions (100%) evoked by angiotensin I and angiotensin II to 30 ± 14% and 26 ± 16% (p < 0.001), respectively. In phenylephrine-precontracted corpora cavernosa, DCM-I pretreatment caused angiotensin II to induce 82 ± 27% relaxation of maximal contraction (p < 0.01) and enhanced (p < 0.001) bradykinin-induced relaxations from 47 ± 8% to 100 ± 5%. In vitro, DCM-I was able to reduce (p < 0.001) the maximal angiotensin-converting enzyme activity to 78 ± 0.24%.
CONCLUSION: Fraction DCM-I was able to antagonize angiotensin II-induced contraction to cause corpus cavernosum relaxation via inhibition of angiotensin II type 1 receptor and enhance bradykinin-induced relaxation through inhibition of angiotensin-converting enzyme.

Matched MeSH terms: Muscle Contraction/drug effects
Esophagogastric junction morphology and contractile integral on high-resolution manometry in asymptomatic healthy volunteers: An international multicenter study

Rogers BD, Rengarajan A, Abrahao L, Bhatia S, Bor S, Carlson DA, et al.

Neurogastroenterol Motil, 2021 06;33(6):e14009.
PMID: 33094875 DOI: 10.1111/nmo.14009

BACKGROUND: Esophagogastric junction contractile integral (EGJ-CI) and EGJ morphology are high-resolution manometry (HRM) metrics that assess EGJ barrier function. Normative data standardized across world regions and HRM manufacturers are limited.
METHODS: Our aim was to determine normative EGJ metrics in a large international cohort of healthy volunteers undergoing HRM (Medtronic, Laborie, and Diversatek software) acquired from 16 countries in four world regions. EGJ-CI was calculated by the same two investigators using a distal contractile integral-like measurement across the EGJ for three respiratory cycles and corrected for respiration (mm Hg cm), using manufacturer-specific software tools. EGJ morphology was designated according to Chicago Classification v3.0. Median EGJ-CI values were calculated across age, genders, HRM systems, and regions.
RESULTS: Of 484 studies (28.0 years, 56.2% F, 60.7% Medtronic studies, 26.0% Laborie, and 13.2% Diversatek), EGJ morphology was type 1 in 97.1%. Median EGJ-CI was similar between Medtronic (37.0 mm Hg cm, IQR 23.6-53.7 mm Hg cm) and Diversatek (34.9 mm Hg cm, IQR 22.1-56.1 mm Hg cm, P = 0.87), but was significantly higher using Laborie equipment (56.5 mm Hg cm, IQR 35.0-75.3 mm Hg cm, P

Matched MeSH terms: Muscle Contraction/physiology
Fulltext No effect of NOS inhibition on skeletal muscle glucose uptake during in situ hindlimb contraction in healthy and diabetic Sprague-Dawley rats

Hong YH, Betik AC, Premilovac D, Dwyer RM, Keske MA, Rattigan S, et al.

Am J Physiol Regul Integr Comp Physiol, 2015 May 15;308(10):R862-71.
PMID: 25786487 DOI: 10.1152/ajpregu.00412.2014

Nitric oxide (NO) has been shown to be involved in skeletal muscle glucose uptake during contraction/exercise, especially in individuals with Type 2 diabetes (T2D). To examine the potential mechanisms, we examined the effect of local NO synthase (NOS) inhibition on muscle glucose uptake and muscle capillary blood flow during contraction in healthy and T2D rats. T2D was induced in Sprague-Dawley rats using a combined high-fat diet (23% fat wt/wt for 4 wk) and low-dose streptozotocin injections (35 mg/kg). Anesthetized animals had one hindlimb stimulated to contract in situ for 30 min (2 Hz, 0.1 ms, 35 V) with the contralateral hindlimb rested. After 10 min, the NOS inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME; 5 μM) or saline was continuously infused into the femoral artery of the contracting hindlimb until the end of contraction. Surprisingly, there was no increase in skeletal muscle NOS activity during contraction in either group. Local NOS inhibition had no effect on systemic blood pressure or muscle contraction force, but it did cause a significant attenuation of the increase in femoral artery blood flow in control and T2D rats. However, NOS inhibition did not attenuate the increase in muscle capillary recruitment during contraction in these rats. Muscle glucose uptake during contraction was significantly higher in T2D rats compared with controls but, unlike our previous findings in hooded Wistar rats, NOS inhibition had no effect on glucose uptake during contraction. In conclusion, NOS inhibition did not affect muscle glucose uptake during contraction in control or T2D Sprague-Dawley rats, and this may have been because there was no increase in NOS activity during contraction.

Matched MeSH terms: Muscle Contraction/drug effects; Muscle Contraction/physiology*
Fulltext Glucose uptake during contraction in isolated skeletal muscles from neuronal nitric oxide synthase μ knockout mice

Hong YH, Frugier T, Zhang X, Murphy RM, Lynch GS, Betik AC, et al.

J Appl Physiol (1985), 2015 May 1;118(9):1113-21.
PMID: 25749441 DOI: 10.1152/japplphysiol.00056.2015

Inhibition of nitric oxide synthase (NOS) significantly attenuates the increase in skeletal muscle glucose uptake during contraction/exercise, and a greater attenuation is observed in individuals with Type 2 diabetes compared with healthy individuals. Therefore, NO appears to play an important role in mediating muscle glucose uptake during contraction. In this study, we investigated the involvement of neuronal NOSμ (nNOSμ), the main NOS isoform activated during contraction, on skeletal muscle glucose uptake during ex vivo contraction. Extensor digitorum longus muscles were isolated from nNOSμ(-/-) and nNOSμ(+/+) mice. Muscles were contracted ex vivo in a temperature-controlled (30°C) organ bath with or without the presence of the NOS inhibitor N(G)-monomethyl-l-arginine (L-NMMA) and the NOS substrate L-arginine. Glucose uptake was determined by radioactive tracers. Skeletal muscle glucose uptake increased approximately fourfold during contraction in muscles from both nNOSμ(-/-) and nNOSμ(+/+) mice. L-NMMA significantly attenuated the increase in muscle glucose uptake during contraction in both genotypes. This attenuation was reversed by L-arginine, suggesting that L-NMMA attenuated the increase in muscle glucose uptake during contraction by inhibiting NOS and not via a nonspecific effect of the inhibitor. Low levels of NOS activity (~4%) were detected in muscles from nNOSμ(-/-) mice, and there was no evidence of compensation from other NOS isoform or AMP-activated protein kinase which is also involved in mediating muscle glucose uptake during contraction. These results indicate that NO regulates skeletal muscle glucose uptake during ex vivo contraction independently of nNOSμ.

Matched MeSH terms: Muscle Contraction/drug effects; Muscle Contraction/physiology*
Neuromuscular effects of candoxin, a novel toxin from the venom of the Malayan krait (Bungarus candidus)

Nirthanan S, Charpantier E, Gopalakrishnakone P, Gwee MC, Khoo HE, Cheah LS, et al.

Br J Pharmacol, 2003 Jun;139(4):832-44.
PMID: 12813007

1 Candoxin (MW 7334.6), a novel toxin isolated from the venom of the Malayan krait Bungarus candidus, belongs to the poorly characterized subfamily of nonconventional three-finger toxins present in Elapid venoms. The current study details the pharmacological effects of candoxin at the neuromuscular junction. 2 Candoxin produces a novel pattern of neuromuscular blockade in isolated nerve-muscle preparations and the tibialis anterior muscle of anaesthetized rats. In contrast to the virtually irreversible postsynaptic neuromuscular blockade produced by curaremimetic alpha-neurotoxins, the neuromuscular blockade produced by candoxin was rapidly and completely reversed by washing or by the addition of the anticholinesterase neostigmine. 3 Candoxin also produced significant train-of-four fade during the onset of and recovery from neuromuscular blockade, both, in vitro and in vivo. The fade phenomenon has been attributed to a blockade of putative presynaptic nicotinic acetylcholine receptors (nAChRs) that mediate a positive feedback mechanism and maintain adequate transmitter release during rapid repetitive stimulation. In this respect, candoxin closely resembles the neuromuscular blocking effects of d-tubocurarine, and differs markedly from curaremimetic alpha-neurotoxins that produce little or no fade. 4 Electrophysiological experiments confirmed that candoxin produced a readily reversible blockade (IC(50) approximately 10 nM) of oocyte-expressed muscle (alphabetagammadelta) nAChRs. Like alpha-conotoxin MI, well known for its preferential binding to the alpha/delta interface of the muscle (alphabetagammadelta) nAChR, candoxin also demonstrated a biphasic concentration-response inhibition curve with a high- (IC(50) approximately 2.2 nM) and a low- (IC(50) approximately 98 nM) affinity component, suggesting that it may exhibit differential affinities for the two binding sites on the muscle (alphabetagammadelta) receptor. In contrast, curaremimetic alpha-neurotoxins have been reported to antagonize both binding sites with equal affinity.

Matched MeSH terms: Muscle Contraction/drug effects; Muscle Contraction/physiology
In vitro anticholinergic and antihistaminic activities of Acorus calamus Linn. leaves extracts

Vijayapandi P, Annabathina V, SivaNagaSrikanth B, Manjunath V, Boggavarapu P, Mohammed P AK, et al.

Afr J Tradit Complement Altern Med, 2012;10(1):95-101.
PMID: 24082330

The present investigation was aimed at determining the effects of hexane, acetone, methanol and aqueous extracts of Acorus calamus leaves (ACHE, ACAE, ACME and ACAQE) on cholinergic and histaminic system using isolated frog rectus abdominis muscle and guinea pig ileum. A dose dependent potentiation of Ach response (anticholinesterase like effect) was found with ACAE and ACME at 0.25, 0.5, 0.75 and 1 mg/ml, but at higher dose of ACAE, ACME, ACAQE and ACHE (5, 20 mg/ml) inhibit the Ach response (antinicotinic effect). These results revealed biphasic effect of Acorus calamus leaves extracts on acetylcholine induced contractile response in isolated frog rectus abdominis muscle preparation (i.e. potentiation effect at lower dose and inhibitory effect at higher dose). Studies on isolated guinea pig ileum demonstrated antihistaminic effect in a dose dependent manner (100-1000 µg/ml) with ACAE, ACME and ACAQE. In addition, the dose dependent inhibition of Ach response (antimuscarinic effect) was observed with ACAE and ACME. In conclusion, Acorus calamus leaves extracts exerts antinicotinic, anticholinesterase like activities in isolated frog rectus abdominis muscle and antihistaminic, antimuscarinic effect in guinea pig ileum. It has been suggested that these observed activities can be further studied for therapeutic potential of Acorus calamus leaves in the treatment of cognitive disorders and asthma.

Matched MeSH terms: Muscle Contraction/drug effects
Spasmolytic effect of citral and extracts of Cymbopogon citratus on isolated rabbit ileum

Devi RC, Sim SM, Ismail R

J Smooth Muscle Res, 2011;47(5):143-56.
PMID: 22104376

Cymbopogon citratus, commonly known as lemongrass, has been shown to have antioxidant, antimicrobial and chemo-protective properties. Citral, a monoterpenoid, is the major constituent of C. citratus that gives off a lemony scent and is postulated to be responsible for most of its actions. In addition, C. citratus has been traditionally used to treat gastrointestinal discomforts, however, the scientific evidence for this is still lacking. Thus, the aim of the present study was to investigate the effect of the extracts of various parts of C. citratus (leaves, stems and roots) and citral on the visceral smooth muscle activity of rabbit ileum. The effect of the test substances were tested on the spontaneous contraction, acetylcholine (ACh)- and KCl-induced contractions. Citral at doses between 0.061 mM to 15.6 mM and the extract of leaves at doses between 0.001 mg/mL to 1 mg/mL significantly reduced the spontaneous, ACh- and KCl-induced ileal contractions. When the ileum was incubated in K(+)-rich-Ca(2+)-free Tyrode's solution, it showed only minute contractions. However, the strength of contraction was increased with the addition of increasing concentrations of CaCl(2). The presence of citral almost abolished the effect of adding CaCl(2), while the leaf extract shifted the calcium concentration-response curve to the right, suggesting a calcium antagonistic effect. These results were similar to that elicited by verapamil, a known calcium channel blocker. In addition, the spasmolytic effect of citral was observed to be reduced by the nitric oxide synthase inhibitor, L-NAME. In conclusion, citral and the leaf extract of C. citratus exhibited spasmolytic activity and it appeared that they may act as calcium antagonists. Furthermore, the relaxant effect of citral, but not that of the leaf extract may be mediated by nitric oxide suggesting the presence of other chemical components in the leaf extract other than citral.

Matched MeSH terms: Muscle Contraction/drug effects*
In vivo antinociceptive and anti-inflammatory activities of dried and fermented processed virgin coconut oil

Zakaria ZA, Somchit MN, Mat Jais AM, Teh LK, Salleh MZ, Long K

Med Princ Pract, 2011;20(3):231-6.
PMID: 21454992 DOI: 10.1159/000323756

The present study was carried out to investigate the antinociceptive and anti-inflammatory activities of virgin coconut oil (VCO) produced by the Malaysian Agriculture Research and Development Institute (MARDI) using various in vivo models.

Matched MeSH terms: Muscle Contraction/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 Contraction/drug effects
Contractile function of smooth muscle retained after overnight storage

Loong BJ, Tan JH, Lim KH, Mbaki Y, Ting KN

Naunyn Schmiedebergs Arch Pharmacol, 2015 Oct;388(10):1061-7.
PMID: 26051407 DOI: 10.1007/s00210-015-1140-3

The functional responses of different overnight-stored in vitro tissues are not clearly described in any animal model. The influence of overnight storage in an animal model may vary between tissue types. We employed Sprague-Dawley rat as our animal model and investigated the functional changes of rat aorta, trachea, bronchus and bladder that were used (i) immediately after surgical removal (denoted as fresh) and (ii) after storage in aerated (95% O2, 5% CO2) Krebs-Ringer bicarbonate solution at 4 °C for 24 h (denoted as stored). The aorta ring was pre-contracted with phenylephrine, and the functional response of the tissue was investigated using isoprenaline, forskolin and carbachol. Carbachol was also used to increase the tone in trachea, bronchus rings and bladder strips. A clear reduced function of endothelium, with a minor if any effect in the smooth muscle function in rat aorta was observed after overnight storage. The contractile response of overnight-stored rat airway (trachea and bronchus) and bladder smooth muscles remained unchanged. Among all tested tissues, only bronchus showed a reduced response rate (only 40% responded) after storage. In vitro rat tissues that are stored in Krebs solution at 4 °C for 24 h can still be used to investigate smooth muscle responses, however, not endothelium-mediated responses for aorta. The influence of overnight storage on different tissues from an animal model (Sprague-Dawley rat in our study) also provides an insight in maximising the use of sacrificed animals.

Matched MeSH terms: Muscle Contraction/drug effects*
Pharmacological, electrophysiological and toxicity studies of Limacia scanden Lour. (Menispermaceae)

Kim Kah Hwi, Wong Bee Lay

J Ethnopharmacol, 1998 Sep;62(2):137-48.
PMID: 9741886

Pharmacological studies showed that Limacia scanden Lour. extracts have sympathomimetic activities similar to noradrenaline (NA). A crude extract of Limacia scanden injected intravenously as a single bolus induced a dose-dependent increase in arterial blood pressure in anaesthetized rats and cats. Pretreatment with a non-specific alpha blocker phentolamine (10(-5) M) blocked this effect, whereas the beta blocker propanolol (10(-5) M) did not. The extract also reduced intestinal motility and this response could be blocked by pretreatment with phentolamine (10(-5) M) and specific alpha1-blocker, prazosin (10(-5) M). In superfused rabbit aorta preparations, it induced an increase in contractions. This effect was blocked by pretreatment with prazosin (10(-5) M), whereas the alpha2-blocker yohimbine (10(-5) M) had only a slight effect. The effects of NA on superfused aorta strip contraction were similar to extract. Toxic symptoms were manifested in less than 5 min when the mice were given 465 mg/kg of extract intraperitoneally. Physiological and behavioural changes observed in dying mice implicated serious malfunctioning of the autonomic nervous system and motor activity. Electrophysiological studies on the tonically autoactive neuron (TAN) of the snail Achantina fulica Férussac revealed that crude extract of Limacia scanden induced excitatory responses which were similar to those of serotonin (5-HT) stimulation. Studies with different ionic compositions of the bathing saline revealed that this excitatory effect of Limacia scanden could be attributed either to release of endogenous serotonin or inhibition of 5-HT reuptake in the CNS. This observation could tentatively be used to provide the framework towards elucidating the mechanism and rationale for the use of this plant in traditional medicine in the treatment of depression and affective disorders.

Matched MeSH terms: Muscle Contraction/drug effects
Effect of steroid hormones on muscarinic receptors of bronchial smooth muscle

Nabishah BM, Morat PB, Kadir BA, Khalid BA

Gen. Pharmacol., 1991;22(2):389-92.
PMID: 1647349

1. Glucocorticosteroid may relieve bronchospasm by mediating changes in the muscarinic receptor concentration and/or its affinity. 2. Cholinergic muscarinic receptors were determined by using Scatchard's plots from radioligand binding assays of 0.13-3.2 nM [3H]quinuclidinyl benzylate binding to the membrane fraction of bronchial smooth muscle (BSM). 3. The concentration of muscarinic receptor in BSM of normal rat was 57 +/- 3 fmol mg protein and the dissociation constant was 0.07 +/- 0.02 nM. Dexamethasone and corticosterone reduced muscarinic receptor concentration to 50-60% of basal with no changes in receptor affinity. No changes were found in rat treated with deoxycorticosterone. 4. These findings suggest that glucocorticoids but not mineralocorticoid relieve bronchospasm at least partly by reducing the cholinergic hypersensitivity.

Matched MeSH terms: Muscle Contraction/drug effects
Effect of acetylcholine and morphine on bronchial smooth muscle contraction and its modulation by steroid hormones

Nabishah BM, Morat PB, Khalid BA, Kadir BA

Clin Exp Pharmacol Physiol, 1990 Dec;17(12):841-7.
PMID: 2092952

1. The effects of corticosteroid pretreatment on acetylcholine (ACH)-induced contraction of bronchial smooth muscle (BSM) were studied. 2. ACH dose-response curves for dexamethasone (DM)- and corticosterone (B)-treated but not deoxycorticosterone (DOC)-treated BSM were significantly shifted to the right; this provides evidence that glucocorticoid treatment reduced the sensitivity of BSM to ACH. 3. Morphine enhanced BSM contraction in response to ACH by 20%. DM suppressed this enhancement. 4. These findings correlated well with the reduction of muscarinic receptor numbers in BSM by glucocorticoids in our previous study. In addition, glucocorticoids reduced the sensitivity of BSM to opioids.

Matched MeSH terms: Muscle Contraction/drug effects

Filters

Please provide feedback to Administrator ([email protected])

External Links