Responses of the isolated rectum of the rainbow lizard (Agama agama) to sympathomimetics

1989 ◽  
Vol 67 (1) ◽  
pp. 68-71
Author(s):  
A. L. Inyang ◽  
D. T. Okpako
Keyword(s):  
Inhibitory Response ◽  
Relaxant Effect ◽  
Dose Dependent ◽  
Noradrenaline And Adrenaline

The relaxant effects of isoprenaline, noradrenaline, and adrenaline on the isolated rectum of the rainbow lizard (Agama agama) were studied. Responses were measured as a reduction of carbachol-induced contractions for each sympathomimetic agent. Isoprenaline, adrenaline, noradrenaline produced a dose-dependent relaxation of this preparation and the order of potency was as given. The pD2 value of 8.15 ± 1.88 obtained for isoprenaline was significantly different (p < 0.05) from those for adrenaline (5.80 ± 0.90) and noradrenaline (5.25 ± 1.18). H35/25, propranolol, and practolol competitively antagonized the relaxant effects of isoprenaline on the isolated lizard rectum. The pA2 values for these β-adrenoceptor antagonists did not differ significantly (at p < 0.05). α-Adrenoceptor antagonists, phentolamine and phenoxybenzamine, failed to alter the relaxant responses of these sympathometics to any appreciable extent. These results are interpreted to suggest that the relaxant effect produced by these sympathomimetics are mediated predominantly by β-adrenoceptors that are not significantly differentiated into subtypes, α-Adrenoceptors in this preparation contribute minimally to the observed inhibitory response following sympathomimetic stimulation.Key words: sympathomimetics, lizard rectum, inhibitory response, β-receptors, α-receptors.

Muscle relaxant activities of pistagremic acid isolated from Pistacia integerrima

2018 ◽  
Vol 73 (11-12) ◽  
pp. 413-416 ◽  
Author(s):  
Abdur Rauf ◽  
Saud Bawazeer ◽  
Ghias Uddin ◽  
Bina S. Siddiqui ◽  
Haroon Khan ◽  
...  
Keyword(s):  
Muscle Relaxant ◽  
Current Work ◽  
Dependent Manner ◽  
Dominant Effect ◽  
Inclined Plane ◽  
Rotarod Test ◽  
Relaxant Effect ◽  
Muscle Relaxant Activity ◽  
Dose Dependent ◽  
Inclined Plane Test

Abstract The aim of the current work was to explore the muscle relaxant effect of pistagremic acid (PA) isolated from Pistacia integerrima in various animal paradigms. In a rotarod test, PA caused a significant (p<0.05) muscle relaxant potential in a dose-dependent manner. When studied in the inclined plane test, pretreatment with PA (5 and 10 mg/kg) caused promising activity (p<0.05) after treatment for 30, 60 and 90 min. The muscle relaxant potential of PA was strongly complimented by the traction and chimney tests, showing a dominant effect after 60 min of treatment. In conclusion, PA possesses strong muscle relaxant activity in various animal-based models.

Influence of purinoceptors' agonists and antagonists on opossum internal anal sphincter

1988 ◽  
Vol 255 (3) ◽  
pp. G389-G394 ◽  
Author(s):  
S. Rattan ◽  
R. Shah
Keyword(s):  
Anal Sphincter ◽  
Internal Anal Sphincter ◽  
Inhibitory Effect ◽  
Inhibitory Response ◽  
Rectal Balloon ◽  
Balloon Distension ◽  
Before And After ◽  
High Doses ◽  
Alpha Chloralose ◽  
Dose Dependent

Studies were performed in alpha-chloralose-anesthetized and pancuronium-treated opossums. Resting internal anal sphincter pressures (IASP) were monitored using low-compliant continuously perfused catheters. P1 and P2 purinoceptor agonists, adenosine and ATP, respectively, administered close intra-arterially, caused dose-dependent decreases in the IASP. The inhibitory effect of these agonists on the IASP was tetrodotoxin resistant. Rectal balloon distension (RD) (which mimics the rectoanal inhibitory reflex) caused volume-dependent IAS relaxation. Electrical stimulation of the sacral nerve (SNS) also produced frequency-dependent decreases in IASP. The inhibitory response to adenosine (P1 purinoceptor agonist), ATP (P2 purinoceptor agonist), RD, and SNS on the internal anal sphincter (IAS) was examined before and after 8-phenyltheophylline (P1 purinoceptor antagonist) and alpha,beta-methylene ATP (P2 purinoceptor antagonist that irreversibly binds and desensitizes P2 purinoceptor). P1 and P2 purinoceptor antagonists produced selective antagonism of the inhibitory responses on the IAS of their respective agonists only. Furthermore, high doses of adenosine and ATP produced desensitization and block of their own actions only. The purinoceptors' antagonists, and the desensitization of purinoceptors by high doses of adenosine and ATP, failed to modify the fall in IASP in response to RD or SNS. From these studies we conclude that distinct inhibitory P1 and P2 purinoceptors are present on the IAS smooth muscle. However, these inhibitory purinoceptors may not be responsible for the rectoanal reflex-mediated IAS relaxation.

scholarly journals The Vasorelaxant Effect ofp-Cymene in Rat Aorta Involves Potassium Channels

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Martapolyana T. M. Silva ◽  
Fernanda P. R. A. Ribeiro ◽  
Maria Alice M. B. Medeiros ◽  
Pedrita A. Sampaio ◽  
Yonara M. S. Silva ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Potassium Channels ◽  
Vascular Smooth Muscle ◽  
Channel Blocker ◽  
Antimicrobial Activities ◽  
Rat Aorta ◽  
Relaxant Effect ◽  
Vasorelaxant Effect ◽  
Dose Dependent ◽  
Relaxing Effect

The monoterpenes are the main constituents of most essential oils andp-cymene is a monoterpene commonly found in various species of aromatic herbs, which has been reported for anti-inflammatory, antinociceptive, and antimicrobial activities. However, there is no report concerning its pharmacological activity on the vascular smooth muscle. The aim of current work was to investigate the effects ofp-cymene in isolated rat aorta and also study its mechanism of action. In this work, we show thatp-cymene has a relaxant effect, in a dose-dependent way, on the vascular smooth muscle, regardless of the presence of the endothelium. Using a nonselective potassium channel blocker, the CsCl, the relaxant effect ofp-cymene was attenuated. In the presence of more selective potassium channels blockers, such as TEA or 4-AP, no change in the relaxant effect ofp-cymene was evidenced, indicating thatBKCaandKVchannels are not involved in that relaxant effect. However, in the presence of glibenclamide or BaCl2,KATPandKirblockers, respectively, the relaxant effect ofp-cymene was attenuated. The data presented indicate thatp-cymene has a relaxing effect on rat aorta, regardless of the endothelium, but with the participation of theKATPandKirchannels.

scholarly journals Tumor necrosis factor induction of endothelial cell urokinase-type plasminogen activator mediated proteolysis of extracellular matrix and its antagonism by gamma-interferon

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 678-687 ◽  
Author(s):  
MJ Niedbala ◽  
MS Picarella
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Plasminogen Activator ◽  
Inhibitory Response ◽  
Dependent Manner ◽  
Ecm Degradation ◽  
Ifn Treatment ◽  
Dose Dependent ◽  
Necrosis Factor ◽  
Pai 1

Tumor necrosis factor (TNF) has a profound capacity to alter the endothelial cell phenotype that includes morphologic and functional changes that may be central for proinflammatory processes. Recent observations have indicated that TNF can promote the synthesis and secretion of urokinase plasminogen activator (uPA) in low passage human endothelial cells that normally release little uPA. In this report we have confirmed and expanded upon these initial observations in human endothelial cells and describe the ability of gamma-interferon (gamma- IFN) to inhibit TNF-induced uPA synthesis and secretion in a dose- dependent manner (0.025 to 25 ng/mL). Analysis of cell-free conditioned medium derived from gamma-IFN-treated cultures by micro-enzyme-linked immunosorbent assay (ELISA) methodologies using uPA- and plasminogen activator inhibitor type 1 (PAI-1)-specific monoclonal antibodies (MoAbs) indicate that the decrease in uPA activity observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) zymography is a direct result of a decrease in extracellular uPA antigen and is not a consequence of increased PAI-1 antigen. These findings are supported by Northern blot analyses that indicate that gamma-IFN treatment of endothelial cells resulted in a decreased steady state level of uPA messenger RNA (mRNA) with no measurable change in PAI-1 mRNA. This inhibitory response is specific for gamma-IFN because alpha-IFN fails to elicit a similar inhibitory response. In addition, TNF augmented extracellular proteolysis of radiolabeled subendothelial extracellular matrix (ECM) in a dose-dependent manner. The observed increase in ECM degradation mediated by TNF treatment of endothelial cells was dependent on the presence of plasminogen and could be inhibited by an anticatalytic uPA MoAb implying the requirement of proteolytically active uPA in this process. gamma-IFN (25 ng/mL) treatment of endothelial cells antagonized TNF-promoted degradation of radiolabeled ECM at a concentration that completely inhibited TNF- mediated uPA expression and activity. In addition, endothelial cells treated with TNF (18 hours) displayed the ability to invade ECM and reorganize individual cells into tube-like structures that were not evident in untreated control cultures when grown on Matrigel-coated culture dishes. gamma-IFN treatment of endothelial cells propagated on Matrigel was observed to inhibit TNF-mediated ECM invasion and tube formation at concentrations that were analogous to those required for the inhibition of uPA expression and activity. In summary, these observations suggest a novel homeostatic control mechanism for endothelial cell regulation of subendothelial ECM degradation promoted by TNF and inhibited by gamma-IFN.(ABSTRACT TRUNCATED AT 400 WORDS).

Endothelium-Dependent Induction of Vasorelaxation by the Butanol Extract of Phellinus igniarius in Isolated Rat Aorta

2006 ◽  
Vol 34 (04) ◽  
pp. 655-665 ◽  
Author(s):  
Dae Gill Kang ◽  
Li Hua Cao ◽  
Jun Kyoung Lee ◽  
Deok Ho Choi ◽  
Seung Ju Kim ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Rat Aorta ◽  
Dependent Manner ◽  
Vascular Relaxation ◽  
Relaxant Effect ◽  
Phellinus Igniarius ◽  
Butanol Extract ◽  
Cgmp Signaling ◽  
Dose Dependent ◽  
Isolated Rat

The butanol extract of Phellinus igniarius (BPI) induced relaxation of the phenylephrin e-precontracted rat aorta in a dose-dependent manner, and its effect was abolished by the removal of functional endothelium. Pretreatment of the aortic tissues with NG -nitro-L-arginine methyl ester (L-NAME), methylene blue, or 1H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin1-one (ODQ) inhibited the vascular relaxation induced by BPI. BPI-induced vascular relaxations were also markedly attenuated by the addition of verapamil or diltiazem, while the relaxant effect of BPI was not blocked by pretreatment with indomethacine, glibenclamide, tetraethylammonium (TEA), atropine, or propranolol. Incubation of endothelium-intact rat aorta with BPI increased the production of cGMP in a dose-dependent manner. These results suggest that BPI dilates vascular smooth muscle via endothelium-dependent nitric oxide-cGMP signaling pathway, with the possible involvement of L-type Ca 2+ channels.

scholarly journals Muscle Relaxant and Sedative-Hypnotic Activities of Extract ofViola betonicifoliain Animal Models Supported by Its Isolated Compound, 4-Hydroxy Coumarin

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Naveed Muhammad ◽  
Mohammad Saeed ◽  
Haroon Khan ◽  
Achyut Adhikari ◽  
Khalid Mohammed Khan
Keyword(s):  
Muscle Relaxant ◽  
Safety Profile ◽  
Methanolic Extract ◽  
Muscle Relaxation ◽  
Antidepressant Activity ◽  
Relaxant Effect ◽  
Whole Plant ◽  
Hydroxy Coumarin ◽  
Isolated Compound ◽  
Dose Dependent

The crude methanolic extract of the whole plant ofViola betonicifolia(VBME) was investigated for anxiolytic, muscle relaxant, sleep induction, antidepressant, and sedative activities) to ascertain its scientific values. VBME showed a significant (P<0.05) dose dependent anxiolytic action in staircase test. In muscle relaxant paradigms, a dose dependent muscle relaxation was observed. For phenobarbitone sleep induction test, VBME notably (P<0.05) reduced the latency time and increased total sleeping duration. Our tested extract was found free of any antidepressant activity, while the movement was significantly (P<0.05) shortened in locomotor activity. The whole plant ofV. betonicifolialed to the isolation of 4-hydroxyl coumarin (4HC) which showed substantial safety profile in acute toxicity test. When challenged in Traction and Chimney tests, it showed significant (P<0.05) muscle relaxant effect in both muscle relaxant paradigms at 20 and 30 mg/kg during various assessment times. Nevertheless, 4HC was devoid of sedative and hypnotic potentials. In conclusion, VBME had strong muscle relaxant and sedative-hypnotic properties, while its isolated compound, 4HC, possessed a significant muscle relaxant action with substantial safety profile without sedative-hypnotic effects.

Endoplasmic reticulum contribution to the relaxant effect of cGMP- and cAMP-elevating agents in feline aorta

2000 ◽  
Vol 278 (6) ◽  
pp. H1856-H1865 ◽  
Author(s):  
Cecilia Mundiña-Weilenmann ◽  
Leticia Vittone ◽  
Gustavo Rinaldi ◽  
Matilde Said ◽  
Gladys Chiappe de Cingolani ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Kinase ◽  
Phosphorylation Site ◽  
Protein Kinase G ◽  
Site Specific ◽  
Relaxant Effect ◽  
Specific Antibodies ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Kinase A

The contribution of endoplasmic reticulum (ER) and phosphorylation of phospholamban (PLB) to the relaxant effect of cGMP- and cAMP-elevating agents was studied in feline aorta. Sodium nitroprusside (NP, 100 μM) completely relaxed contracture induced by 10 μM norepinephrine. This NP-induced relaxation was partially prevented by tetraethylammonium, suggesting that a fraction of NP-induced relaxation was mediated by activation of K+ channels. In the absence and presence of tetraethylammonium, the relaxant effect of NP was associated with a significant increase in Ser16 phosphorylation of PLB immunodetected by phosphorylation site-specific antibodies. The relaxant effect of NP on aortic strips precontracted with 80 mM KCl was significantly reduced by 1 μM thapsigargin. This decrease, which represents the ER contribution to the relaxant effect of NP, reached 23 ± 9% at 100 μM NP and was closely associated with a dose-dependent increase in Ser16 phosphorylation (128 ± 49% over control at 100 μM NP). Effects of NP were associated with a significant increase in activity of protein kinase G and were mimicked by 8-bromo-cGMP. Forskolin produced a dose-dependent relaxant effect on KCl-induced contracture, which reached 64 ± 8% at 50 μM and was associated with an increase in phosphorylation of Ser16residue of PLB (88 ± 18% over control). Thapsigargin reduced this relaxant effect by 38 ± 9%. 8-Bromo-cAMP mimicked effects of forskolin. The ER-mediated relaxant effect and the increase in Ser16 phosphorylation produced by forskolin were partially blocked by the protein kinase A inhibitor H-89 (5 μM). The results indicate that ER partially contributes to the relaxant effect of NP and forskolin in feline aorta. This effect may be mediated by the associated increase in Ser16 phosphorylation of PLB.

scholarly journals Antidiarrheal and antispasmodic activities of Polygonum bistorta rhizomes are mediated predominantly through K+ channels activation

2015 ◽  
Vol 10 (3) ◽  
pp. 627 ◽  
Author(s):  
Muhammad Zeeshan Ali ◽  
Khalid Hussain Janbaz ◽  
Malik Hassan Mehmood ◽  
Anwar Hassan Gilani
Keyword(s):  
Tetraethylammonium Chloride ◽  
Relaxant Effect ◽  
Complete Relaxation ◽  
High K ◽  
Rabbit Jejunum ◽  
Low K ◽  
Dose Dependent ◽  
Antagonist Effect

<p class="Abstract"><em>Polygonum bistorta</em> is a popular medicinal herb used to treat diarrhea. This study provides pharmacological basis to its folk use in diarrhea using <em>in vivo</em> and <em>in vitro</em> assays. Administration of<em> P. bistorta</em>  rhizomes extract to mice offered protection against castor oil-induced diarrhea at 300-1,000 mg/kg and was found safe up to the dose of 5 g/kg. In isolated rabbit jejunum, the extract caused a dose-dependent relaxation of spontaneous and low K<sup>+</sup> (25 mM)-induced contractions with weak effect against high K<sup>+ </sup>(80 mM). In tissues pretreated with glibenclamide or tetraethylammonium chloride (TEA), the relaxant effect of the extract was markedly inhibited by TEA only. While verapamil showed complete relaxation of spontaneous, low K<sup>+</sup>, low K<sup>+</sup> with TEA and high K<sup>+</sup>-induced contractions. In guinea-pig ileum, mild atropine-sensitive effect was observed. This study indicates that <em>P. bistorta</em> possesses anti-diarrheal and antispasmodic activities mediated predominantly through K<sup>+</sup>-channels activation along with weak Ca<sup>++</sup> antagonist effect.</p><p> </p>

scholarly journals Tumor necrosis factor induction of endothelial cell urokinase-type plasminogen activator mediated proteolysis of extracellular matrix and its antagonism by gamma-interferon

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 678-687 ◽  
Author(s):  
MJ Niedbala ◽  
MS Picarella
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Plasminogen Activator ◽  
Inhibitory Response ◽  
Dependent Manner ◽  
Ecm Degradation ◽  
Ifn Treatment ◽  
Dose Dependent ◽  
Necrosis Factor ◽  
Pai 1

Abstract Tumor necrosis factor (TNF) has a profound capacity to alter the endothelial cell phenotype that includes morphologic and functional changes that may be central for proinflammatory processes. Recent observations have indicated that TNF can promote the synthesis and secretion of urokinase plasminogen activator (uPA) in low passage human endothelial cells that normally release little uPA. In this report we have confirmed and expanded upon these initial observations in human endothelial cells and describe the ability of gamma-interferon (gamma- IFN) to inhibit TNF-induced uPA synthesis and secretion in a dose- dependent manner (0.025 to 25 ng/mL). Analysis of cell-free conditioned medium derived from gamma-IFN-treated cultures by micro-enzyme-linked immunosorbent assay (ELISA) methodologies using uPA- and plasminogen activator inhibitor type 1 (PAI-1)-specific monoclonal antibodies (MoAbs) indicate that the decrease in uPA activity observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) zymography is a direct result of a decrease in extracellular uPA antigen and is not a consequence of increased PAI-1 antigen. These findings are supported by Northern blot analyses that indicate that gamma-IFN treatment of endothelial cells resulted in a decreased steady state level of uPA messenger RNA (mRNA) with no measurable change in PAI-1 mRNA. This inhibitory response is specific for gamma-IFN because alpha-IFN fails to elicit a similar inhibitory response. In addition, TNF augmented extracellular proteolysis of radiolabeled subendothelial extracellular matrix (ECM) in a dose-dependent manner. The observed increase in ECM degradation mediated by TNF treatment of endothelial cells was dependent on the presence of plasminogen and could be inhibited by an anticatalytic uPA MoAb implying the requirement of proteolytically active uPA in this process. gamma-IFN (25 ng/mL) treatment of endothelial cells antagonized TNF-promoted degradation of radiolabeled ECM at a concentration that completely inhibited TNF- mediated uPA expression and activity. In addition, endothelial cells treated with TNF (18 hours) displayed the ability to invade ECM and reorganize individual cells into tube-like structures that were not evident in untreated control cultures when grown on Matrigel-coated culture dishes. gamma-IFN treatment of endothelial cells propagated on Matrigel was observed to inhibit TNF-mediated ECM invasion and tube formation at concentrations that were analogous to those required for the inhibition of uPA expression and activity. In summary, these observations suggest a novel homeostatic control mechanism for endothelial cell regulation of subendothelial ECM degradation promoted by TNF and inhibited by gamma-IFN.(ABSTRACT TRUNCATED AT 400 WORDS).

scholarly journals The Anti-tumor Effect of the Light Petroleum Extract from Pulsatilla Chinensis (Bunge) Regel

2008 ◽  
Vol 3 (5) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Min Zhang ◽  
Zhihang Song ◽  
Dan Wang ◽  
Lin Cheng ◽  
Wenrong Jin ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Polyunsaturated Fatty Acids ◽  
Ethanol Extract ◽  
Positive Control ◽  
Inhibitory Response ◽  
Light Petroleum ◽  
Pulsatilla Chinensis ◽  
Unusual Phenomenon ◽  
Main Components ◽  
Dose Dependent

The crude ethanol extract of Pulsatilla chinensis (Bunge) Regel roots was extracted successively with light petroleum, dichloromethane and n-butanol. The light petroleum fraction (PEF) exhibited potent anti-proliferation activity on HL60 cells with an IC50 value of 14 μg/mL. As a result, ICR mice transplanted with tumor strain S180 were employed for testing the effectiveness of drug administration of PEF. The tumor inhibitory rate was 36.7% at a dose of 20 mg/kg/d, which was higher than the positive control, which produced 31.5% inhibition. However, an unusual phenomenon was observed in that the tumor inhibitory response was reverse dose-dependent since tumor inhibition was only 19.5% at a dose of 180 mg/kg/d. GC-MS revealed that the main components of the PEF were C-19 and C-22 polyunsaturated fatty acids. Previous studies had revealed that polyunsaturated fatty acids exhibit either anti-tumor or tumor promoting activities, and so it is proposed that the effects of PEF on tumor growth is dependent on dosage.

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