Reduction of intrinsic sinoatrial frequency and norepinephrine response of the exercised rat

1977 ◽  
Vol 55 (4) ◽  
pp. 813-820 ◽  
Author(s):  
Richard L. Hughson ◽  
John R. Sutton ◽  
J. Desmond Fitzgerald ◽  
Norman L. Jones
Keyword(s):  
Sinoatrial Node ◽  
Parasympathetic Nervous System ◽  
Control Group ◽  
Response Curves ◽  
Chronotropic Response ◽  
In Vitro Measurements ◽  
The Right

Physical training is associated with a reduction of intrinsic sinoatrial activity; the present study examined the role of the parasympathetic nervous system in this reduction. Six groups of rats were studied for 10 weeks: inactive control; treadmill exercised; parasympathetic receptor blockade with atropine; exercise plus atropine; parasympathetic receptor stimulation with carbachol; and exercise plus carbachol. In vivo ISF (cardiac frequency 20 min after injection of propranolol and atropine) was measured at 3-week intervals. At the end of 10 weeks the right atrium was excised, in vitro measurements were made of ISF, and chronotropic dose–response curves to acetylcholine and norepinephrine were established. In vivo, ISF was reduced with time, the greatest reduction being found in the exercise plus atropine group; the treadmill-exercised and the atropine-treated groups also had a greater reduction than the control group. In vitro, no differences were observed in acetylcholine responses. The maximum norepinephrine chronotropic response was reduced in the treadmill-exercised and the exercise plus atropine groups. The maximum norepinephrine-induced frequency correlated with the in vitro ISF (r = 0.75). Thus, ISF was reduced with training, but this effect was independent of parasympathetic activity. The properties of the sinoatrial node which set ISF also influenced the maximum norepinephrine response.

scholarly journals Pharmacologically mechanistic basis for the traditional uses of Rumex acetosa in gut motility disorders and emesis

2015 ◽  
Vol 10 (3) ◽  
pp. 548 ◽  
Author(s):  
Musaddique Hussain ◽  
Shahid Masood Raza ◽  
Khalid Hussain Janbaz
Keyword(s):  
Rumex Acetosa ◽  
Response Curves ◽  
Motility Disorders ◽  
Traditional Uses ◽  
Antiemetic Activity ◽  
Rabbit Jejunum ◽  
Mechanistic Basis ◽  
The Right

<p class="Abstract"><em>In vitro</em> and<em> in vivo</em> studies were undertaken to evaluate the pharmacologically mechanistic background to validate the traditional uses of <em>Rumex acetosa</em> in the treatment of emesis and gastrointestinal motility disorders such as constipation and diarrhea. In rabbit jejunum preparation, methanolic extract of <em>R. acetosa</em> (0.01-1.0 mg/mL) caused a transient spasmogenic effect, followed by the spasmolytic effect (3-10 mg/mL). In presence of atropine, spasmogenic effect was blocked while spasmolytic effect was emerged, suggesting that spasmogenic effect was mediated through activation of muscarinic receptors. Extract inhibited the K<sup>+ </sup>(80 mM)-induced contraction, suggesting Ca<sup>2+</sup>-cha-nnel blockade, which was further confirmed when pretreatment of tissue with extract shifted the Ca<sup>2+ </sup>concentration-response curves to the right, similarly as verapamil.<em> R. acetosa</em> also exhibited the significant antiemetic activity (p&lt;0.05) against different emetogenic stimuli, when compared with chlorpromazine. This study confirms the presence of gut modulator (spasmogenic and spasmolytic) and antiemetic activates, validating its traditional uses.</p><p> </p>

Anti-inflammatory, Antioxidant, Lung and Liver Protective Activity of Galaxaura oblongata as Antagonistic Efficacy against LPS using Hematological Parameters and Immunohistochemistry as Biomarkers

2021 ◽  
Vol 19 ◽  
Author(s):  
Asmaa Nabil-Adam ◽  
Mohamed A. Shreadah
Keyword(s):  
Protective Effect ◽  
Hematological Parameters ◽  
Control Group ◽  
In Vivo Assays ◽  
Induction Group ◽  
Anti Inflammatory ◽  
In Vitro Effects

Background: This study aimed to investigate the potential bioactivity and the ameliorative role of Galaxaura oblongata (G. oblongata) against LPS-induced toxicity by using hematological parameters. Objective: It is aimed also to examine its protective effect using the immunohistochemistry of liver and lungs as biomarkers in male BALB/C albino mice. Materials and Methods: the current study carried out using different in-vitro and in-vivo assays such as phytochemical, antioxidants, anti-inflammatory for in-vitro where the hematological and immunohistochemistry for lung and liver were investigated in vivo. Results: There are no previous studies were performed to investigate the in vivo and in vitro effects of the G. oblongata extracts as antioxidant and anti-inflammatory due to their rareness compared to other red algae. LPS treated mice revealed a significant decrease in total number of WBCs, RBCs, platelets, and HGB%, MPV, MCV and MCHC compared to the control group. On contrast, the HCT and MCHC were increased in the induction group which was treated with LPS compared to the control group. Furthermore, the immunohistochemistry results of the present study revealed the protective effect of G. oblongata compared to the induction group. G. oblongata can be used as protective marine natural products against the toxicity induced by LPS. Conclusion: It exhibited a significant ameliorative role against the alterations in the hematological parameters and immunohistochemistry of liver and lungs, and helps to reduce as well as coordinate the acute inflammations caused by TNF.

Studies on antihypertensive and antispasmodic activities of Andropogon muricatus Retz.This article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.

2007 ◽  
Vol 85 (9) ◽  
pp. 911-917 ◽  
Author(s):  
Anwar H. Gilani ◽  
Abdul J. Shah ◽  
Khalid H. Janbaz ◽  
Shahida P. Ahmed ◽  
Muhammad N. Ghayur
Keyword(s):  
Calcium Channel ◽  
Rabbit Aorta ◽  
Natural Health Products ◽  
Response Curves ◽  
Medicinal Uses ◽  
Health Products ◽  
Rabbit Jejunum ◽  
The Right

The aqueous-methanolic crude extract of Andropogon muricatus (Am.Cr) was investigated pharmacologically to determine some of its medicinal uses in cardiovascular and gastrointestinal disorders. A series of in vivo and in vitro studies were conducted to evaluate dose-dependent effects of Am.Cr on mean arterial pressure (MAP), cardiac and vascular contractions, and to further investigate the potential mechanism of action. Intravenous administration of Am.Cr (10–50 mg/kg) caused a fall (18%–56%) in MAP in normotensive rats under anesthesia. When tested in isolated guinea pig atria, Am.Cr (0.03–5.0 mg/mL) exhibited a cardiodepressant effect on the rate and force of spontaneous contractions. In isolated rabbit aorta, Am.Cr caused inhibition of K+ (80 mmol/L)-induced contractions at a lower concentration than of phenylephrine. In isolated rabbit jejunum preparations, Am.Cr (0.01–0.10 mg/mL) caused relaxation of spontaneous and high K+ (80 mmol/L)-induced contractions, suggesting that the spasmolytic effect is mediated possibly through calcium channel blockade (CCB). The CCB activity was confirmed when pretreatment of the tissue with Am.Cr (0.03–0.1 mg/mL) shifted the Ca2+ dose–response curves to the right, similar to that caused by verapamil. These data indicate that the blood pressure-lowering and spasmolytic effects of Am.Cr are mediated possibly through a calcium channel blocking activity. Phytochemical screening of Am.Cr revealed the presence of phenols, saponins, tannins, and terpenes, which may be responsible for the observed vasodilator, cardiodepressant, and antispasmodic activities. This study shows potential with respect to its medicinal use in cardiovascular and gut disorders.

ANG II- and TxA2-induced mesenteric vasoconstriction in rats is mediated by separate cell signaling pathways

1999 ◽  
Vol 277 (1) ◽  
pp. H1-H7 ◽  
Author(s):  
Johannes Bauer ◽  
Cécile Dau ◽  
Alessandro Cavarape ◽  
Franz Schaefer ◽  
Heimo Ehmke ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Dose Response ◽  
Ang Ii ◽  
Response Curves ◽  
Intracellular Ca ◽  
The Right ◽  
Activate Protein Kinase ◽  
Cell Signaling Pathways

Studies in vitro have demonstrated that vasoconstrictor agents increase intracellular Ca2+ and activate protein kinase C (PKC) to elevate vascular tone. The aim of the present study was to determine the importance of these signaling pathways for angiotensin II (ANG II) and thromboxane A2(TxA2) in regulating mesenteric blood flow (MBF) in vivo. In anesthetized rats increasing doses of ANG II or the TxA2 agonist U-46619 were administered into the superior mesenteric artery to reduce MBF. Intra-arterial infusion of inhibitors served to examine the contribution of different pathways: 8-(diethylamino)octyl 3,4,5-trimethoxybenoate hydrochloride (TMB-8) to inhibit intracellular Ca2+ release, nifedipine to block transmembrane Ca2+ influx through the L-type Ca2+ channel, and staurosporine to inhibit PKC. Each of the inhibitors attenuated ANG II-induced reductions in MBF, and all dose-response curves were shifted to the right to an approximately threefold higher ANG II dose. Combinations of the inhibitors revealed that their effects were additive; together they abolished the vasoconstrictor action of ANG II completely. In contrast, the dose-response curve for U-46619 was not affected by any of the inhibitors infused either separately or together. The results demonstrate that a rise in intracellular Ca2+ and activation of PKC are major mediators of the vasoconstrictor effect of ANG II in mesenteric circulation, but they play a subordinate role, if any, for the effects of TxA2. Because TxA2 plays a major role only under pathological conditions, the uncontrolled vasoconstriction appears to be associated with the recruitment of novel signal transduction pathways.

Enhanced β-Catenin/Foxo1 Activity Alleviates Pulmonary Fibrosis by Inhibiting β-Catenin/T Cell Factor Signaling

2020 ◽  
Vol 10 (2) ◽  
pp. 182-188
Author(s):  
Kun Gui ◽  
Yu Huang ◽  
Meijin Wang ◽  
Jun Yang
Keyword(s):  
Extracellular Matrix ◽  
Pulmonary Fibrosis ◽  
Inflammatory Cytokines ◽  
Underlying Mechanism ◽  
Control Group ◽  
Kidney Fibrosis ◽  
Mrc5 Cell

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia, resulting in chronic respiratoryfailure and eventually death. β-catenin/Foxo1 showed a protective property in kidney fibrosis, but the role of β-catenin/Foxo1 in IPF was unclear. Our study aimed to investigate the role of β-catenin/Foxo1 in IPF and explore its underlying mechanism. The IPF model was established by injection of bleomycin (BLM) in vivo and stimulation by TGF-β1 in MRC5 cell in vitro. Haematoxylin-eosin staining and Masson’s trichrome staining were performed to examine histopathological injury in lung. Protein expression of corresponding genes was detected using western blot. Immunofluorescence staining assay was carried out to detect the expression of β-catenin, Foxo1, TCF and α-SMA. The expression levels of inflammatory cytokines were determined using ELISA kit assay. The results showed that BLM induced a serious pulmonary injury and proliferated fibroblasts. A higher interaction of β-catenin with TCF and a lower interaction of β-catenin with Foxo1 was found in BLM group compared to the control group. TGF-β1 promoted β-catenin/TCF, whereas ICG-001 inhibited β-catenin/TCF, and promoted β-catenin/Foxo1. Furthermore, ICG-001 reversed TGF-β1 induced largely production of inflammatory cytokines and accumulation of extracellular matrix, as well as high expression of α-SMA. However, AS1842856, a FOXO1 antagonist, strengthened the effects induced by TGF-β1. In summary, our study revealed that β-catenin/Foxo1 protected against IPF through inhibiting inflammatory response and extracellular matrix accumulation, providing an alternative approach to explain the potential mechanism of IPF and seek for more effective therapeutic drugs.

scholarly journals Decreased Fast Ripples in the Hippocampus of Rats with Spontaneous Recurrent Seizures Treated with Carbenoxolone and Quinine

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Consuelo Ventura-Mejía ◽  
Laura Medina-Ceja
Keyword(s):  
Gap Junctions ◽  
Gap Junction ◽  
High Frequency Oscillations ◽  
The Mean ◽  
Eeg Recordings ◽  
The Right ◽  
Spontaneous Recurrent Seizures

Background. In models of temporal lobe epilepsy and in patients with this pathology, high frequency oscillations called fast ripples (FRs, 250–600 Hz) can be observed. FRs are considered potential biomarkers for epilepsy and, in the light of manyin vitroandin silicostudies, we thought that electrical synapses mediated by gap junctions might possibly modulate FRsin vivo.Methods. Animals with spontaneous recurrent seizures induced by pilocarpine administration were implanted with movable microelectrodes in the right anterior and posterior hippocampus to evaluate the effects of gap junction blockers administered in the entorhinal cortex. The effects of carbenoxolone (50 nmoles) and quinine (35 pmoles) on the mean number of spontaneous FR events (occurrence of FRs), as well as on the mean number of oscillation cycles per FR event and their frequency, were assessed using a specific algorithm to analyze FRs in intracranial EEG recordings.Results. We found that these gap junction blockers decreased the mean number of FRs and the mean number of oscillation cycles per FR event in the hippocampus, both during and at different times after carbenoxolone and quinine administration.Conclusion. These data suggest that FRs may be modulated by gap junctions, although additional experimentsin vivowill be necessary to determine the precise role of gap junctions in this pathological activity associated with epileptogenesis.

Measuring the effect of avermectins and milbemycins on somatic muscle contraction of adult Haemonchus contortus and on motility of Ostertagia circumcincta in vitro

Parasitology ◽  
2014 ◽  
Vol 141 (7) ◽  
pp. 948-956 ◽  
Author(s):  
JANINA DEMELER ◽  
GEORG VON SAMSON-HIMMELSTJERNA ◽  
NICHOLAS C. SANGSTER
Keyword(s):  
Muscle Contraction ◽  
Haemonchus Contortus ◽  
Anthelmintic Resistance ◽  
Parasitic Nematodes ◽  
Response Curves ◽  
Drug Potency ◽  
The Right ◽  
Sites Of Action

SUMMARYThe mechanism of anthelmintic resistance against the widely used macrocyclic lactones (MLs) is still not fully understood. Pharyngeal, somatic body muscles and the ovijector have been proposed as putative sites of action as well as resistance. In the present study the effects of three avermectins and three milbemycins on adult parasitic nematodes were evaluated in vitro. The Muscle Transducer system was used to investigate the effects of MLs on muscle contraction in female Haemonchus contortus and effects on motility were measured in Ostertagia (Teladorsagia) circumcincta using the Micromotility Meter. Concentration-response curves for all substances in both systems shifted to the right in the resistant isolates. Resistance was present to ivermectin (IVM) and its components IVM B1a and IVM B1b, suggesting that both components are involved in the mode of action and resistance. No consistent patterns of potency and resistance of the substances were observed except that milbemycins generally showed lower resistance ratios (RRs) than IVM. IVM and IVM B1b were the most potent inhibitors of contraction and motility in both susceptible isolates and also showed the highest RR in both species. Low RRs for milbemycins recorded in vitro for highly resistant isolates in vivo suggest that other factors such as pharmacokinetics influence drug potency in vivo.

The Lack of Effects of Phototherapy on Neonatal Oxygen Dissociation Curves and Hemoglobin Concentration in Vivo

PEDIATRICS ◽  
1977 ◽  
Vol 59 (6) ◽  
pp. 1027-1031
Author(s):  
Barry D. Chandler ◽  
William J. Cashore ◽  
Pierre J. P. Monin ◽  
William Oh
Keyword(s):  
Serum Bilirubin ◽  
Hemoglobin Concentration ◽  
Control Group ◽  
Dissociation Curve ◽  
Oxygen Dissociation ◽  
The Right ◽  
Dissociation Curves ◽  
2,3 Dpg

Phototherapy has been shown to cause hemolysis of fetal red cells and a shift to the right in the neonatal oxygen dissociation curve (ΔP50) in vitro. To determine if these parameters act similarly in vivo, we have studied 16 icteric infants before and after phototherapy and compared them with eight control infants studied at birth and at 3 days of age, measuring the change in P50, 2,3-diphosphoglycerate (2,3-DPG), serum bilirubin, the percent of bilirubin/albumin saturation, and the hemoglobin concentration in the two groups. Following phototherapy, in the icteric infants there was a shift to the right in the O2 dissociation curve of + 1.7 mm Hg, a rise in 2,3-DPG of 2.26 µmol/gm Hb, a fall in serum bilirubin of 4.3 mg/100 ml, a decrease in percent bilirubin/albumin saturation of 12.4%, and a drop in hemoglobin of 1.1 gm/100 ml. The control group showed a ΔP50 of + 2.0 mm Hg, a rise in 2,3-DPG of 3.67 µmol/gm Hb, an increase in serum bilirubin of 3.2 mg/100 ml, an increase in percent bilirubin/albumin saturation of 9.3%, and a fall in hemoglobin of 0.3 gm/100 ml. Significant differences between the groups were seen only in the changes in bilirubin concentration and percent bilirubin/albunmin saturation. The magnitude of changes in P50, 2,3-DPG, and hemoglobin concentration was similar in the phototherapy and control groups and was related to the expected changes with reference to postnatal age. These results suggest that phototherapy in vivo neither affects fetal erythrocytic affinity for oxygen nor causes hemolysis.

Antidiarrheal Activity of Ethanol Extract of Ophioglossum Vulgatum In Mice And Spasmolytic Effect on Smooth Muscle Contraction of Isolated Jejunum In Rabbits

2020 ◽  
Author(s):  
Jianwu Zhang ◽  
Lan Yang ◽  
Yingying Fang ◽  
Jing Li ◽  
Chunxia Gu ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
High Performance ◽  
Chemical Constituents ◽  
Ethanol Extract ◽  
Gastrointestinal Diseases ◽  
Control Group ◽  
Response Curves ◽  
Antidiarrheal Activity

Abstract BackgroundOphioglossum vulgatum Linn. (Ophioglossaceae) (OV), which is traditionally used on wounds and burns, enjoys a reputation as the king of medicine in Taiwan. There are few studies on its role in gastrointestinal diseases. Our aim was to assess the antidiarrheal and spasmolytic effect of the ethanol whole plant extract of Ophioglossum vulgatum (EWOV).MethodsStudy was conducted from June 2018 to July 2019. The chemical constituents of EWOV were analyzed by high performance liquid chromatography (HPLC). In vivo, the antidiarrheal activity of EWOV (125, 250 and 500 mg/kg; orally) in castor oil-induced Kun Ming mice was evaluated. In vitro, the effect of EWOV (0.01-10 mg/mL) on the spontaneous contraction of isolated rabbit jejunum smooth muscle was studied. Verapamil was the positive control group in both vivo and vitro studies. The jejunum stripes were pre-contracted by ACh (10-5 M) and KCl (60 mM) which could induce the jejunum spasm. The possible spasmolytic effect was analyzed in the pretreatment of the jejunum preparations with EWOV (0.3, 1 mg/mL) or verapamil (0.03, 0.1 µM) in Ca2+-free and high-K+ (60 mM) solution containing EDTA.ResultsEWOV (250 and 500 mg/kg) exhibited antidiarrheal effect. EWOV (0.01-10 mg/mL) inhibited the spontaneous and ACh/KCl-induced contraction with an EC50 value of 1.46 (0.89-2.04), 1.06 (0.63-1.48) and 0.48 (0.29-0.67), and it shifted the concentration-response curves of CaCl2 to right with decreased in max, similar to verapamil. ConclusionsEWOV has significant antidiarrheal and spasmolytic effect, possibly by mediating calcium channel blocking activity, this provides the pharmacological basis for use in gastrointestinal disorders.

Neutral endopeptidase modulates neurotensin-induced airway contraction

1989 ◽  
Vol 66 (5) ◽  
pp. 2338-2343 ◽  
Author(s):  
T. D. Djokic ◽  
D. J. Dusser ◽  
D. B. Borson ◽  
J. A. Nadel
Keyword(s):  
Smooth Muscle ◽  
Serine Proteases ◽  
Neutral Endopeptidase ◽  
Smooth Muscle Contraction ◽  
Response Curves ◽  
Terminal Fragment ◽  
Carboxypeptidase N

To determine the role of endogenous neutral endopeptidase (NEP) (also called enkephalinase, EC 3.4.24.11) in regulating neurotensin-induced airway contraction, we used phosphoramidon, a specific NEP inhibitor, in the guinea pig. In studies in vitro, neurotensin and the COOH-terminal fragment neurotensin-(8–13) contracted strips of bronchial smooth muscle in a concentration-dependent fashion (P less than 0.001). In contrast, the NH2-terminal fragment neurotensin-(1–11) and the COOH-terminal fragment neurotensin-(12–13), the main fragments of neurotensin hydrolysis by NEP, had no effect. Phosphoramidon (10(-5) M) did not change resting tension but shifted the concentration-response curves to neurotensin to lower concentrations (P less than 0.001), whereas inhibitors of kininase II, aminopeptidases, serine proteases, and carboxypeptidase N were without effect. Removing the epithelium increased the contractile response to neurotensin (P less than 0.001), and phosphoramidon further increased the response to neurotensin in these tissues (P less than 0.001). Similar results were obtained in studies in vivo using aerosolized neurotensin and phosphoramidon. These results suggest that endogenous NEP in the airways modulates the effects of neurotensin on airway smooth muscle contraction by inactivating the peptide.

Sign in / Sign up

Export Citation Format

Share Document