Isbufylline, a Xanthine Derivative, Inhibits Bronchoconstrictor Responses Produced by Stimulation of Capsaicin-sensitive Sensory Nerves in Guinea-pig: 'In Vitro' and 'In Vivo' Evidence

1993 ◽  
Vol 6 (4) ◽  
pp. 279-286 ◽  
Author(s):  
S. Meini ◽  
L. Ballati ◽  
S. Evangelista ◽  
S. Manzini
Keyword(s):  
Guinea Pig ◽  
Sensory Nerves ◽  
Xanthine Derivative ◽  
Stimulation Of

Peripheral sympathetic pathways to gastroduodenal region of the guinea pig

1983 ◽  
Vol 245 (3) ◽  
pp. G369-G375
Author(s):  
D. L. Kreulen ◽  
T. C. Muir ◽  
J. H. Szurszewski
Keyword(s):  
Guinea Pig ◽  
Celiac Plexus ◽  
Intraluminal Pressure ◽  
Gastric Distension ◽  
Electrical Nerve Stimulation ◽  
Reflex Pathways ◽  
Gastroduodenal Motility ◽  
Stimulation Of

The sympathetic pathways to the stomach and duodenum of the guinea pig were studied by electrical nerve stimulation and by gastric distension in vitro and in vivo. The in vitro preparation consisted of the stomach and duodenum connected by para-arterial nerves to the celiac plexus. Gastroduodenal motility was measured with intraluminal pressure catheters. Stimulation of splanchnic nerves resulted in inhibition of propulsive contractions of both the stomach and duodenum. Stimulation of the left gastric nerve inhibited the stomach but not the duodenum, and stimulation of the gastroduodenal nerve inhibited the duodenum only. When the gastroduodenal nerve was stimulated, excitatory postsynaptic potentials were elicited in 18% of the cells from which intracellular recordings were made in the celiac ganglia. When the stomach was distended to a pressure of 5-7 cmH2O, propulsive contractions in the duodenum stopped in 86% of the distensions in the in vivo preparations and in 62% of the distensions in the in vitro preparations. Section of the gastroduodenal nerve eliminated the distension-induced inhibition of duodenal propulsion in vitro. These experiments describe the efferent sympathetic pathways to the celiac plexus of the guinea pig and demonstrate reflex pathways to the celiac plexus that can mediate a gastroduodenal inhibitory reflex.

Permissive role of α-tocopherol in the stimulation of aldosterone by sodium depletion in the guinea pig

1996 ◽  
Vol 134 (6) ◽  
pp. 758-763 ◽  
Author(s):  
K Möbius ◽  
A Redmann ◽  
HH Hiller ◽  
W Oelkers ◽  
V Bähr
Keyword(s):  
Vitamin E ◽  
Guinea Pig ◽  
Plasma Aldosterone ◽  
Sodium Depletion ◽  
Aldosterone Secretion ◽  
Permissive Role ◽  
Stimulation Of

Möbius K, Redmann A, Hiller HH, Oelkers W, Bähr V. Permissive role of α-tocopherol in the stimulation of aldosterone by sodium depletion in the guinea pig. Eur J Endocrinol 1996;134:758–63. ISSN 0804–4643 To investigate the role of vitamin E in aldosterone synthesis, in vivo and in vitro studies were done in α-tocopherol-depleted guinea pigs. Seventy-one days of low vitamin E intake (< 5 mg/kg feed) reduced the concentration of α-tocopherol in serum, liver and adrenals to low levels with no signs of hypovitaminosis. Aldosterone secretion was stimulated by 15 days on a low sodium diet (200 mg/kg feed) in controls and vitamin E-depleted animals. Sodium depletion in controls stimulated plasma aldosterone by 335%. Vitamin E depletion reduced the stimulation of plasma aldosterone to only 112% (p < 0.05). In vitro aldosterone secretion by adrenal cells from sodium-depleted animals was 252% higher than secretion by cells from controls. This enhancement of in vitro aldosterone secretion following in vivo sodium depletion was abolished completely by combined in vivo vitamin E and sodium depletion (p < 0.05). No significant differences between groups were found for plasma renin activity, adrenocorticotrophin and serum potassium, suggesting that intra-adrenal mechanisms like damage by enhanced lipid peroxidation in α-tocopherol-depleted animals rather than changes in humoral aldosterone-regulating factors are the cause of the attenuated aldosterone response to sodium depletion. Volker Bähr, Abteilung Endokrinologie, Medizinische Klinik, Klinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, D-12000 Berlin, Germany

scholarly journals Prostaglandin D2 and the role of the DP1, DP2 and TP receptors in the control of airway reflex events

2014 ◽  
Vol 45 (4) ◽  
pp. 1108-1118 ◽  
Author(s):  
Sarah A. Maher ◽  
Mark A. Birrell ◽  
John J. Adcock ◽  
Michael A. Wortley ◽  
Eric D. Dubuis ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Receptor Agonist ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Vagal Afferents ◽  
Prostaglandin D2 ◽  
Airway Reflex ◽  
Guinea Pig Model

Prostaglandin D2 (PGD2) causes cough and levels are increased in asthma suggesting that it may contribute to symptoms. Although the prostaglandin D2 receptor 2 (DP2) is a target for numerous drug discovery programmes little is known about the actions of PGD2 on sensory nerves and cough.We used human and guinea pig bioassays, in vivo electrophysiology and a guinea pig conscious cough model to assess the effect of prostaglandin D2 receptor (DP1), DP2 and thromboxane receptor antagonism on PGD2 responses.PGD2 caused cough in a conscious guinea pig model and an increase in calcium in airway jugular ganglia. Using pharmacology and receptor-deficient mice we showed that the DP1 receptor mediates sensory nerve activation in mouse, guinea pig and human vagal afferents. In vivo, PGD2 and a DP1 receptor agonist, but not a DP2 receptor agonist, activated single airway C-fibres. Interestingly, activation of DP2 inhibited sensory nerve firing to capsaicin in vitro and in vivo.The DP1 receptor could be a therapeutic target for symptoms associated with asthma. Where endogenous PGD2 levels are elevated, loss of DP2 receptor-mediated inhibition of sensory nerves may lead to an increase in vagally associated symptoms and the potential for such adverse effects should be investigated in clinical studies with DP2 antagonists.

Conversion and release of an intermediate in vasopressin–neurophysin biosynthesis in the guinea-pig

1984 ◽  
Vol 103 (3) ◽  
pp. 347-354 ◽  
Author(s):  
P. M. Jones ◽  
T. Saermark ◽  
I. C. A. F. Robinson
Keyword(s):  
Guinea Pig ◽  
The Other ◽  
Concomitant Increase ◽  
Temperature Dependent ◽  
Neural Lobe ◽  
In Vivo Labelling ◽  
Processed Form ◽  
Stimulation Of

ABSTRACT Guinea-pig neural lobes contain appreciable amounts of neurophysin with a glycopeptide extension (NPGP) which may represent a partially processed form of the arginine vasopressin (AVP) precursor. We have now studied the turnover and release of the NPGP component using a combination of in-vivo radiolabel incorporation and high pressure liquid chromatography. Measurement of the neural lobe content of 35S-labelled peptides at various times after hypothalamic injection of [35S]cysteine demonstrated that the oxytocin-related products accumulated more rapidly than the AVP-related products. The relative amounts of [35S]cysteine incorporated into NPGP and the AVP-related neurophysin (NPavp) changed markedly with time after in-vivo labelling. In-vitro incubation of neurosecretory granules prepared from neural lobes 4 h after radiolabel injection produced a time- and temperature-dependent conversion of NPGP to NPavp. Incubation at 37 °C for 4 h produced a 30% decrease in [35S]NPGP with a concomitant increase in [35S]NPavp, whilst there were no changes in the other 35S-labelled components. In-vitro stimulation of radiolabelled neural lobes by 56 mm-K+ evoked a Ca++-dependent release of NPGP as well as the other expected neurosecretory components, and the amount of NPGP released reflected its neural lobe content. We conclude that the NPGP component found in guinea-pig neural lobes is a biosynthetic intermediate, most of which is further processed to NPavp. However, some NPGP may also be secreted from the neural lobe in an intact form. J. Endocr. (1984) 103, 347–354

Inhibition of Human and Animal Platelet Adhesiveness to Glass Bead Columns by Adenosine, Dipyridamole, Chlorpromazine and Acetylsalicylic Acid

1976 ◽  
Vol 36 (02) ◽  
pp. 401-410 ◽  
Author(s):  
Buichi Fujttani ◽  
Toshimichi Tsuboi ◽  
Kazuko Takeno ◽  
Kouichi Yoshida ◽  
Masanao Shimizu
Keyword(s):  
Guinea Pig ◽  
Acetylsalicylic Acid ◽  
Guinea Pigs ◽  
Glass Bead ◽  
Animal Species ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Platelet Adhesiveness

SummaryThe differences among human, rabbit and guinea-pig platelet adhesiveness as for inhibitions by adenosine, dipyridamole, chlorpromazine and acetylsalicylic acid are described, and the influence of measurement conditions on platelet adhesiveness is also reported. Platelet adhesiveness of human and animal species decreased with an increase of heparin concentrations and an increase of flow rate of blood passing through a glass bead column. Human and rabbit platelet adhesiveness was inhibited in vitro by adenosine, dipyridamole and chlorpromazine, but not by acetylsalicylic acid. On the other hand, guinea-pig platelet adhesiveness was inhibited by the four drugs including acetylsalicylic acid. In in vivo study, adenosine, dipyridamole and chlorpromazine inhibited platelet adhesiveness in rabbits and guinea-pigs. Acetylsalicylic acid showed the inhibitory effect in guinea-pigs, but not in rabbits.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Contamination of erythropoietin by endotoxin: in vivo and in vitro effects on murine erythropoiesis

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 146-158 ◽  
Author(s):  
KS Zuckerman ◽  
PJ Quesenberry ◽  
J Levin ◽  
R Sullivan
Keyword(s):  
Significant Inhibition ◽  
Erythropoietic Activity ◽  
Limulus Amebocyte Lysate ◽  
Endogenous Erythropoietin ◽  
Significant Change ◽  
In Vitro Effects ◽  
Stimulation Of

Abstract Endotoxin was detected in all erythropoietin preparations tested and was removed from four lots, without loss of erythropoietic activity, by adsorption with limulus amebocyte lysate. Comparison of adsorbed (endotoxin-depleted) and nonadsorbed (endotoxin-containing) erythropoietin preparations demonstrated significant inhibition of CFU- e and BFU-e in vitro by nonadsorbed erythropoietin at concentrations higher than 0.25 U/ml and 2.0 U/ml, respectively. CFU-e and BFU-e were inhibited significantly by readdition in vitro of 10(-5)-10(-3) mug of endotoxin per unit of limulus-adsorbed erythropoietin. Administration of saline or 6 U of nonadsorbed or adsorbed erythropoietin twice a day for 4 days of CF1 mice resulted in reticulocyte counts of 2.1%, 9.9%, and 15.9%, respectively. Nonadsorbed erythropoietin resulted in a 29% decrease in erythropoiesis, a 42% decrease in CFU-e, and a 16% increase in granulopoiesis in the marrow, whereas adsorbed erythropoietin caused a 28% increase in erythropoiesis, no significant change in CFU-e and a 19% decrease in granulopoiesis in the marrow. Both preparations resulted in marked increases in splenic erythropoiesis and granulopoiesis. The effects of adsorbed erythropoietin are similar to those produced following stimulation of hematopoiesis by endogenous erythropoietin. Hemopoietic changes induced by nonadsorbed erythropoietin in vivo and in vitro are affected substantially by contamination of the erythropoietin preparations with endotoxin.

A Novel α-Conotoxin Identified by Gene Sequencing Is Active in Suppressing the Vascular Response to Selective Stimulation of Sensory Nerves in Vivo†

Biochemistry ◽  
2003 ◽  
Vol 42 (22) ◽  
pp. 6904-6911 ◽  
Author(s):  
D. W. Sandall ◽  
N. Satkunanathan ◽  
D. A. Keays ◽  
M. A. Polidano ◽  
X. Liping ◽  
...  
Keyword(s):  
Gene Sequencing ◽  
Sensory Nerves ◽  
Vascular Response ◽  
Selective Stimulation ◽  
Stimulation Of

Metabolic importance of Na+/K+-ATPase activity during sea urchin development.

1997 ◽  
Vol 200 (22) ◽  
pp. 2881-2892 ◽  
Author(s):  
P Leong ◽  
D Manahan
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Sea Urchin ◽  
Sodium Pump ◽  
Sea Water ◽  
Strongylocentrotus Purpuratus ◽  
Lytechinus Pictus ◽  
Stimulation Of

Early stages of animal development have high mass-specific rates of metabolism. The biochemical processes that establish metabolic rate and how these processes change during development are not understood. In this study, changes in Na+/K+-ATPase activity (the sodium pump) and rate of oxygen consumption were measured during embryonic and early larval development for two species of sea urchin, Strongylocentrotus purpuratus and Lytechinus pictus. Total (in vitro) Na+/K+-ATPase activity increased during development and could potentially account for up to 77 % of larval oxygen consumption in Strongylocentrotus purpuratus (pluteus stage) and 80 % in Lytechinus pictus (prism stage). The critical issue was addressed of what percentage of total enzyme activity is physiologically active in living embryos and larvae and thus what percentage of metabolism is established by the activity of the sodium pump during development. Early developmental stages of sea urchins are ideal for understanding the in vivo metabolic importance of Na+/K+-ATPase because of their small size and high permeability to radioactive tracers (86Rb+) added to sea water. A comparison of total and in vivo Na+/K+-ATPase activities revealed that approximately half of the total activity was utilized in vivo. The remainder represented a functionally active reserve that was subject to regulation, as verified by stimulation of in vivo Na+/K+-ATPase activity in the presence of the ionophore monensin. In the presence of monensin, in vivo Na+/K+-ATPase activities in embryos of S. purpuratus increased to 94 % of the maximum enzyme activity measured in vitro. Stimulation of in vivo Na+/K+-ATPase activity was also observed in the presence of dissolved alanine, presumably due to the requirement to remove the additional intracellular Na+ that was cotransported with alanine from sea water. The metabolic cost of maintaining the ionic balance was found to be high, with this process alone accounting for 40 % of the metabolic rate of sea urchin larvae (based on the measured fraction of total Na+/K+-ATPase that is physiologically active in larvae of S. purpuratus). Ontogenetic changes in pump activity and environmentally induced regulation of reserve Na+/K+-ATPase activity are important factors that determine a major proportion of the metabolic costs of sea urchin development.

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