Cholecystokinin affects gastric emptying and stomach motility in the rainbow trout Oncorhynchus mykiss

In this study, we describe new methods for recording gastric emptying and in vivo measurements of intragastric pressure in fish. Using these methods, we investigated the effects of the sulphated octapeptide of cholecystokinin (CCK8) on gastric emptying and on stomach motility in vivo and in vitro. Gastric emptying of 99Tcm-labelled food was measured in swimming fish by using a gamma camera, counting consecutive 2.5 min periods for 18–42 h. After 20 h, 55.3+/−4.0 % of the labelled food remained in the stomach of the control fish (mean s.e.m., N=9). Vascular infusion of CCK8 (25 pmol kg-1 h-1) delayed gastric emptying so that 70.4+/−4.8 % of the labelled food remained in the stomach after 20 h (N=8). Gastric pressure changes in vivo were measured using a balloon surgically fitted into the cardiac or pyloric part of the stomach. In the cardiac part, intra-arterial infusion of CCK8 at 0.1 nmol kg-1 h-1 resulted in a decrease in the frequency and amplitude of rhythmic contractions, while higher doses started/increased contractions. Atropine blocked much of the basal contractile activity, but did not influence the CCK8-induced inhibition of contractile activity. The pyloric part of the stomach was unaffected by intra-arterial infusion of CCK8 or atropine. In vitro perfusion of the stomach (with a balloon placed in the cardiac part to record motility) with CCK8 at high concentrations (10(−7)mol l-1 and above) augmented the spontaneous contractions, while lower concentrations had inconsistent effects. In addition, CCK8 (10(−7) to 10(−6)mol l-1) decreased the amplitude of spontaneous contractions in longitudinal strip preparations, usually in combination with an increase in the resting tension. The decrease in amplitude was not affected by the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester hydrochloride (L-NAME; 10(−4)mol l-1). Depending on the concentration and experimental arrangement, CCK8 had either inhibitory or excitatory effects on the cardiac stomach, suggesting the possible presence of different types of CCK receptor. We conclude that the predominant effect of CCK8 in vivo may be a slowing down of gastric emptying, presumably coinciding with a release of bile into the duodenum.

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Effects of gentamicin on spontaneous and agonist-induced in vitro contractions of isolated myometrial tissue from pregnant cows

Medycyna Weterynaryjna ◽

10.21521/mw.6333 ◽

2019 ◽

Vol 75 (11) ◽

pp. 6333-2019

Author(s):

MURAT YUKSEL ◽

HALIS OCAL ◽

AHMET AYAR

Keyword(s):

Contractile Activity ◽

Isometric Force ◽

Displacement Transducer ◽

Organ Bath ◽

Dependent Manner ◽

Gentamicin Sulphate ◽

Spontaneous Contractions ◽

Dose Dependent

The aim of the present study is to examine the effects of gentamicin sulphate on spontaneous, oxytocin and PGF2α induced in vitro contractions of myometrium isolated from pregnant cows. Myometrial strips were obtained from healthy pregnant cows and suspended in a covered organ bath filled with Krebs’ solution at 37°C (pH 7.4) continuously bubbled with 95% oxygen and 5% carbon dioxide: isometric contractions were recorded using an isometric force displacement transducer. After the stabilization of spontaneous contractile activity during a 90-minute equilibration period, contractions were recorded for 20 minutes (control). Gentamicin sulphate was then added to the tissue bath cumulatively and the responses were recorded every 20-minutes for each consecutive dose of gentamicin. In agonist-induced contractions, oxytocin or PGF2α was added to the tissue bath at the end of the equilibration period and the same protocol was followed to investigate the effects gentamicin on these agonist-induced contractions. Gentamicin decreased the frequency and inhibited the amplitude of the spontaneous contractions in a dose dependent manner (p < 0.05). The mean frequency and amplitude of oxytocin-induced contractions was significantly inhibited by the application of gentamicin (p < 0.05). Gentamicin also inhibited the contractions induced by PGF2α in a dose dependent manner (p < 0.05). This study showed gentamicin inhibited, depending on the dosage, oxytocin and PGF2α induced contractions of myometrium isolated from pregnant cows. Upon clinically examining the findings obtained by the study, gentamicin can be used as an antibacterial in septic abort and chorioamniotis in order to prevent premature birth, abortion and early uterus contractions. Further studies are necessary to test whether the same effect will take place in vivo and to examine the effects of longterm use of gentamicin on offsprings.

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Metallic Elements (Cu, Zn, Ni and Mn) Toxicity Effects Determination on a Fresh Water Fish Cyprinus Carpio (Common Carp) Laboratory Acclimatized

Revista de Chimie ◽

10.37358/rc.17.8.5750 ◽

2017 ◽

Vol 68 (8) ◽

pp. 1711-1715

Author(s):

Stefania Gheorghe ◽

Gabriela Geanina Vasile ◽

Cristina Gligor ◽

Irina Eugenia Lucaciu ◽

Mihai Nita Lazar

Keyword(s):

Cyprinus Carpio ◽

Aquatic Organisms ◽

Control Fish ◽

Toxicity Tests ◽

Fresh Water Fish ◽

Metallic Elements ◽

Mn Toxicity ◽

Vitro Effect

Metallic elements copper (Cu), zinc (Zn), nickel (Ni) and manganese (Mn) are some of the most commonly found in water and sediment samples collected from the Danube - Danube Delta. These elements are important as essential micronutrients, being normally present at low concentrations in biological organisms, but in high concentrations they become toxic with immediate and delayed effects. The role of this metals is still controversial, that�s why bioconcentration potential is so important. In this non-clinical study, we tested in vitro effect of heavy metals on carp, Cyprinus carpio, reproducing in vivo presence of Cu, Zn, Ni and Mn in the Romanian�s surface water. The toxicity tests were performed according to OECD 203 by detecting the average (50%) lethal concentration - LC50 on aquatic organisms (freshwater fish) at 96h. The results pointed out that, copper value for LC 50 at 96h was estimated as 3.4 mg/L (concentrations tested in the range of 0.1 - 4.75 mg/L). Zinc value for LC 50 at 96h was estimated as 20.8 mg/L (concentrations tested in the range of 0.028 � 29.6 mg/L). Nickel value for LC 50 at 96h was estimated as 40.1 mg/L (concentrations tested in the range of 0.008 - 84.5 mg/L). For manganese the mortality effects has recorded at LC 50 at 96h at estimated value higher than 53 mg/L (concentrations tested in the range of 0.04 - 53.9 mg/L). The accuracy of the testing metals concentration was insured by the screening of the dilution water, as well as food and control fish, acclimated in laboratory conditions.

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Genetic deletion of trkB.T1 increases neuromuscular function

AJP Cell Physiology ◽

10.1152/ajpcell.00469.2010 ◽

2012 ◽

Vol 302 (1) ◽

pp. C141-C153 ◽

Cited By ~ 19

Author(s):

Susan G. Dorsey ◽

Richard M. Lovering ◽

Cynthia L. Renn ◽

Carmen C. Leitch ◽

Xinyue Liu ◽

...

Keyword(s):

Calcium Release ◽

Contractile Activity ◽

Muscle Tension ◽

Neuromuscular Synapse ◽

Neuromuscular Function ◽

In Vitro Assays ◽

Tyrosine Kinase Receptor ◽

Akt Activation

Neurotrophin-dependent activation of the tyrosine kinase receptor trkB.FL modulates neuromuscular synapse maintenance and function; however, it is unclear what role the alternative splice variant, truncated trkB ( trkB.T1), may have in the peripheral neuromuscular axis. We examined this question in trkB.T1 null mice and demonstrate that in vivo neuromuscular performance and nerve-evoked muscle tension are significantly increased. In vitro assays indicated that the gain-in-function in trkB.T1 −/− animals resulted specifically from an increased muscle contractility, and increased electrically evoked calcium release. In the trkB.T1 null muscle, we identified an increase in Akt activation in resting muscle as well as a significant increase in trkB.FL and Akt activation in response to contractile activity. On the basis of these findings, we conclude that the trkB signaling pathway might represent a novel target for intervention across diseases characterized by deficits in neuromuscular function.

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Contractile activity is required for the expression of neonatal myosin heavy chain in embryonic chick pectoral muscle cultures.

The Journal of Cell Biology ◽

10.1083/jcb.103.6.2153 ◽

1986 ◽

Vol 103 (6) ◽

pp. 2153-2161 ◽

Cited By ~ 51

Author(s):

L C Cerny ◽

E Bandman

Keyword(s):

Monoclonal Antibody ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Contractile Activity ◽

Pectoral Muscle ◽

Chicken Muscle ◽

High K ◽

Muscle Cultures ◽

Spontaneous Contractions

The expression of neonatal myosin heavy chain (MHC) was examined in developing embryonic chicken muscle cultures using a monoclonal antibody (2E9) that has been shown to be specific for that isoform (Bandman, E., 1985, Science (Wash. DC), 227: 780-782). After 1 wk in vitro some myotubes could be stained with the antibody, and the number of cells that reacted with 2E9 increased with time in culture. All myotubes always stained with a second monoclonal antibody that reacted with all MHC isoforms (AG19) or with a third monoclonal antibody that reacted with the embryonic but not the neonatal MHC (EB165). Quantitation by ELISA of an extract from 2-wk cultures demonstrated that the neonatal MHC represented between 10 and 15% of the total myosin. The appearance of the neonatal isoform was inhibited by switching young cultures to medium with a higher [K+] which has been shown to block spontaneous contractions of myotubes in culture. Furthermore, if mature cultures that reacted with the neonatal antibody were placed into high [K+] medium, neonatal MHC disappeared from virtually all myotubes within 3 d. The effect of high [K+] medium was reversible. When cultures maintained in high [K+] medium for 2 wk were placed in standard medium, which permitted the resumption of contractile activity, within 24 h cells began to react with the neonatal specific antibody, and by 72 h many myotubes were strongly positive. Since similar results were also obtained by inhibiting spontaneous contractions with tetrodotoxin, we suggest that the development of contractile activity is not only associated with the maturation of myotubes in culture, but may also be the signal that induces the expression of the neonatal MHC.

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Role of prostaglandins in contractile activity of the ampulla of the rabbit oviduct

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1980.238.2.e157 ◽

1980 ◽

Vol 238 (2) ◽

pp. E157-E166 ◽

Cited By ~ 2

Author(s):

M. J. Harper ◽

L. W. Coons ◽

D. A. Radicke ◽

B. J. Hodgson ◽

G. Valenzuela

Keyword(s):

Spontaneous Activity ◽

Contractile Activity ◽

Prostaglandin E ◽

High Dose ◽

Field Stimulation ◽

Prostaglandin Synthetase ◽

Response Curves ◽

Normal Tissues

Contractile activity of the ampulla of rabbit oviducts removed 24 h after an ovulating injection was studied in vitro. Spontaneous activity, field-stimulated activity, and response to phenylephrine were studied in normal, reversed, and scraped (endosalpinx removed) sections of tissues in the presence or absence of inhibitors of prostaglandin synthetase (8 or 51 micrograms/ml indomethacin or 10 or 100 micrograms/ml 5,8,11,14-eicosatetraynoic acid (ETA)). The effects of in vivo treatment with 10 mg/kg of indomethacin on the same responses were examined. Scraped tissues produced more prostaglandin E and F (measured by radioimmunoassay) than did normal tissues, and this production was suppressed by 10 micrograms/ml of indomethacin or 100 micrograms/ml of ETA. Production of prostaglandin by normal tissues was not depressed by these compounds in vitro, but was significantly reduced by pretreatment of the animals with indomethacin in vivo. In the absence of the endosalpinx, the myosalpinx exhibited spontaneous activity and responded to field stimulation and phenylephrine. Scraped and reversed tissues, however, showed a faster decline in response to field stimulation than normal tissues, and this was due to the traumatization. By contrast, traumatization increased the sensitivity of the tissue to respond to phenylephrine. Inhibition of prostaglandin synthetase by low doses of indomethacin or ETA prevented desensitization of the tissue to field stimulation, but this desensitization was little affected by the higher doses of indomethacin in vitro or in vivo. ETA did not affect the phenylephrine dose-response curves and nor did 8 micrograms/ml of indomethacin, whereas the high dose was inhibitory. Spontaneous activity was only affected by the in vivo pretreatment with indomethacin, which prevented the decline in activity of scraped tissue with time.

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Molecular and functional characterization of somatostatin-type signalling in a deuterostome invertebrate

Open Biology ◽

10.1098/rsob.200172 ◽

2020 ◽

Vol 10 (9) ◽

pp. 200172

Author(s):

Ya Zhang ◽

Luis Alfonso Yañez Guerra ◽

Michaela Egertová ◽

Cleidiane G. Zampronio ◽

Alexandra M. Jones ◽

...

Keyword(s):

Functional Characterization ◽

The Body ◽

Pharmacological Characterization ◽

Cardiac Stomach ◽

Physiological Processes ◽

Pharmacological Tests ◽

The Central Nervous System

Somatostatin (SS) and allatostatin-C (ASTC) are structurally and evolutionarily related neuropeptides that act as inhibitory regulators of physiological processes in mammals and insects, respectively. Here, we report the first molecular and functional characterization of SS/ASTC-type signalling in a deuterostome invertebrate—the starfish Asterias rubens (phylum Echinodermata). Two SS/ASTC-type precursors were identified in A. rubens (ArSSP1 and ArSSP2) and the structures of neuropeptides derived from these proteins (ArSS1 and ArSS2) were analysed using mass spectrometry. Pharmacological characterization of three cloned A. rubens SS/ASTC-type receptors (ArSSR1–3) revealed that ArSS2, but not ArSS1, acts as a ligand for all three receptors. Analysis of ArSS2 expression in A. rubens using mRNA in situ hybridization and immunohistochemistry revealed stained cells/fibres in the central nervous system, the digestive system (e.g. cardiac stomach) and the body wall and its appendages (e.g. tube feet). Furthermore, in vitro pharmacological tests revealed that ArSS2 causes dose-dependent relaxation of tube foot and cardiac stomach preparations, while injection of ArSS2 in vivo causes partial eversion of the cardiac stomach. Our findings provide new insights into the molecular evolution of SS/ASTC-type signalling in the animal kingdom and reveal an ancient role of SS-type neuropeptides as inhibitory regulators of muscle contractility.

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Degranulation enhances release of a stable contractile factor from rabbit polymorphonuclear leukocytes

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1998.274.5.h1545 ◽

1998 ◽

Vol 274 (5) ◽

pp. H1545-H1551

Author(s):

Justin R. Hamilton ◽

Joanne L. Hart ◽

Owen L. Woodman

Keyword(s):

Slow Rate ◽

Polymorphonuclear Leukocytes ◽

Cytochalasin B ◽

Contractile Activity ◽

90 C 10 ◽

Isolated Aorta ◽

Aortic Contraction ◽

Factor Release

We investigated the release of a stable contractile factor(s) from rabbit isolated polymorphonuclear leukocytes (PMNs; 108cells/ml) incubated in Tyrode buffer at 37°C. PMNs were untreated, stimulated with N-formylmethionyl-leucyl-phenylalanine (FMLP; 0.1 μM), or degranulated with cytochalasin B (1 μM) in combination with FMLP (0.1 μM). Products from unstimulated PMNs incubated for 60 min caused significantly greater contraction of rabbit isolated aorta (0.56 ± 0.12 g, n = 8) than did products released from PMNs during a 5-min incubation (0.32 ± 0.07 g, n = 11, P < 0.05). Stimulation alone did not affect contractile factor release; however, products released from degranulated PMNs caused significantly greater aortic contraction (0.48 ± 0.08 g, n = 5) than products from nondegranulated PMNs (0.24 ± 0.04 g, n = 5, P < 0.05) after a 5-min incubation. The contractile activity of PMN-derived products was virtually abolished by heat (90°C, 10 min) or protease (trypsin; 166 U/ml, 5 h) treatment. These findings suggest a PMN-derived protein vasoconstrictor(s) is spontaneously released at a slow rate in vitro and that degranulation can enhance this rate of release. Because PMN degranulation in vivo is associated with inflammation, these results support suggestions that PMN-derived contractile factors may contribute to the impaired blood flow observed during postischemic reperfusion.

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UDP-glucose modulates gastric function through P2Y14 receptor-dependent and -independent mechanisms

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.90363.2008 ◽

2009 ◽

Vol 296 (4) ◽

pp. G923-G930 ◽

Cited By ~ 23

Author(s):

Anna K. Bassil ◽

Sophie Bourdu ◽

Karen A. Townson ◽

Alan Wheeldon ◽

Emma M. Jarvie ◽

...

Keyword(s):

Gastric Emptying ◽

Muscle Tension ◽

Electrical Field Stimulation ◽

P2y Receptors ◽

Nucleotide Sugar ◽

Significant Difference ◽

Stomach Motility ◽

Rat Gut

P2Y receptors have been reported to modulate gastrointestinal functions. The newest family member is the nucleotide-sugar receptor P2Y14. P2ry14 mRNA was detected throughout the rat gut, with the highest level being in the forestomach. We investigated the role of the receptor in stomach motility using cognate agonists and knockout (KO) mice. In rat isolated forestomach, 100 μM UDP-glucose and 100 μM UDP-galactose both increased the baseline muscle tension (BMT) by 6.2 ± 0.6 and 1.6 ± 0.6 mN ( P < 0.05, n = 3–4), respectively, and the amplitude of contractions during electrical field stimulation (EFS) by 3.7 ± 1.7 and 4.3 ± 2.5 mN ( P < 0.05, n = 3–4), respectively. In forestomach from wild-type (WT) mice, 100 μM UDP-glucose increased the BMT by 1.0 ± 0.1 mN ( P <0.05, n = 6) but this effect was lost in the KO mice (change of −0.1 ± 0.1 mN, n = 6). The 100 μM UDP-glucose also increased the contraction amplitude during EFS in this tissue from the WT animals (0.9 ± 0.4 mN, P < 0.05, n = 6) but not from the KO mice (0.0 ± 0.2 mN, n = 6). In vivo, UDP-glucose at 2,000 mg/kg ip reduced gastric emptying in rats by 49.7% ( P < 0.05, n = 4–6) and in WT and KO mice by 56.1 and 66.2%, respectively ( P < 0.05, n = 7–10) vs. saline-treated control animals. There was no significant difference in gastric emptying between WT and KO animals receiving either saline or d-glucose. These results demonstrate a novel function of the P2Y14 receptor associated with contractility in the rodent stomach that does not lead to altered gastric emptying after receptor deletion and an ability of UDP-glucose to delay gastric emptying without involving the P2Y14 receptor.

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GPR119 Regulates Murine Glucose Homeostasis Through Incretin Receptor-Dependent and Independent Mechanisms

Endocrinology ◽

10.1210/en.2010-1047 ◽

2010 ◽

Vol 152 (2) ◽

pp. 374-383 ◽

Cited By ~ 44

Author(s):

Grace Flock ◽

Dianne Holland ◽

Yutaka Seino ◽

Daniel J. Drucker

Keyword(s):

Insulin Secretion ◽

Gastric Emptying ◽

Glucose Tolerance ◽

Glucose Homeostasis ◽

Peptide Yy ◽

Cell Receptor ◽

Dependent Manner ◽

Glucagon Like Peptide 1

Abstract G protein-coupled receptor 119 (GPR119) was originally identified as a β-cell receptor. However, GPR119 activation also promotes incretin secretion and enhances peptide YY action. We examined whether GPR119-dependent control of glucose homeostasis requires preservation of peptidergic pathways in vivo. Insulin secretion was assessed directly in islets, and glucoregulation was examined in wild-type (WT), single incretin receptor (IR) and dual IR knockout (DIRKO) mice. Experimental endpoints included plasma glucose, insulin, glucagon, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and peptide YY. Gastric emptying was assessed in WT, Glp1r−/−, DIRKO, Glp2r−/−, and GPR119−/− mice treated with the GPR119 agonist AR231453. AR231453 stimulated insulin secretion from WT and DIRKO islets in a glucose-dependent manner, improved glucose homeostasis, and augmented plasma levels of GLP-1, GIP, and insulin in WT and Gipr−/−mice. In contrast, although AR231453 increased levels of GLP-1, GIP, and insulin, it failed to lower glucose in Glp1r−/− and DIRKO mice. Furthermore, AR231453 did not improve ip glucose tolerance and had no effect on insulin action in WT and DIRKO mice. Acute GPR119 activation with AR231453 inhibited gastric emptying in Glp1r−/−, DIRKO, Glp2r−/−, and in WT mice independent of the Y2 receptor (Y2R); however, AR231453 did not control gastric emptying in GPR119−/− mice. Our findings demonstrate that GPR119 activation directly stimulates insulin secretion from islets in vitro, yet requires intact IR signaling and enteral glucose exposure for optimal control of glucose tolerance in vivo. In contrast, AR231453 inhibits gastric emptying independent of incretin, Y2R, or Glp2 receptors through GPR119-dependent pathways. Hence, GPR119 engages multiple complementary pathways for control of glucose homeostasis.

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