scholarly journals Adenosine-mediated hypotension in in vivo guinea-pig: receptors involved and role of NO

2001 ◽  
Vol 134 (4) ◽  
pp. 745-752 ◽  
Author(s):  
P Nieri ◽  
E Martinotti ◽  
V Calderone ◽  
M C Breschi
Keyword(s):  
Guinea Pig

scholarly journals The subcellular localization of di- and tri-peptide hydrolase activity in guinea-pig small intestine

1970 ◽  
Vol 120 (1) ◽  
pp. 195-203 ◽  
Author(s):  
T. J. Peters
Keyword(s):  
Guinea Pig ◽  
Brush Border ◽  
Soluble Fraction ◽  
Subcellular Fractionation ◽  
Border Region ◽  
Protein Digestion ◽  
Kinetic Assay ◽  
Brush Borders

1. Two different subcellular fractionation techniques were applied to guinea-pig intestinal mucosa and the composition of the brush borders prepared by the two methods were compared. 2. By using a kinetic assay system the subcellular distribution of activity against ten dipeptides and five tripeptides was studied. 3. Only small amounts (5–10%) of activity against dipeptides were found in the brush-border region, the enzymes being concentrated in the cytosol. 4. Significant amounts (10–60%) of activity against tripeptides were found in the brush border with the remainder largely present in the soluble fraction. 5. The relevance of these studies to the localization in vivo and the possible role of peptidases in protein digestion is discussed.

scholarly journals Molecular, Biological, and In Vivo Characterization of the Guinea Pig Cytomegalovirus (CMV) Homologs of the Human CMV Matrix Proteins pp71 (UL82) and pp65 (UL83)

2004 ◽  
Vol 78 (18) ◽  
pp. 9872-9889 ◽  
Author(s):  
Alistair McGregor ◽  
Fenyong Liu ◽  
Mark R. Schleiss
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Matrix Proteins ◽  
Wild Type ◽  
Viral Dna ◽  
Guinea Pig Cytomegalovirus ◽  
Human Cmv ◽  
Hsv 1

ABSTRACT We recently identified the genes encoding the guinea pig cytomegalovirus (GPCMV) homologs of the upper and lower matrix proteins of human CMV, pp71 (UL82) and pp65 (UL83), which we designated GP82 and GP83, respectively. Transient-expression studies with a GP82 plasmid demonstrated that the encoded protein targets the nucleus and that the infectivity and plaquing efficiency of cotransfected GPCMV viral DNA was enhanced by GP82. The transactivation function of GP82 was not limited to GPCMV, but was also observed for a heterologous virus, herpes simplex virus type 1 (HSV-1). This was confirmed by its ability to complement the growth of an HSV-1 VP16 transactivation-defective mutant virus in an HSV viral DNA cotransfection assay. Study of a GP82 “knockout” virus (and its attendant rescuant), generated on a GPCMV bacterial artificial chromosome construct, confirmed the essential nature of the gene. Conventional homologous recombination was used to generate a GP83 mutant to examine the role of GP83 in the viral life cycle. Comparison of the one-step growth kinetics of the GP83 mutant (vAM409) and wild-type GPCMV indicated that GP83 protein is not required for viral replication in tissue culture. The role of GP83 in vivo was examined by comparing the pathogenesis of wild-type GPCMV, vAM409, and a control virus, vAM403, in guinea pigs. The vAM409 mutant was significantly attenuated for dissemination in immunocompromised strain 2 guinea pigs, suggesting that the GP83 protein is essential for full pathogenicity in vivo.

scholarly journals Release and fixation of CO2 by guinea-pig kidney tubules metabolizing aspartate

1992 ◽  
Vol 284 (3) ◽  
pp. 697-703
Author(s):  
G Martin ◽  
C Michoudet ◽  
N Vincent ◽  
G Baverel
Keyword(s):  
Guinea Pig ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Co2 Fixation ◽  
Carbon Oxidation ◽  
Kidney Tubules ◽  
Pig Kidney ◽  
Glutamine Synthesis ◽  
Oxoglutarate Dehydrogenase

1. The metabolism of L-[U-14C]aspartate, L-[1-14C]aspartate and L-[4-14C]aspartate was studied in isolated guinea-pig kidney tubules. 2. Oxidation of C-1 plus that of C-4 of aspartate accounted for 90-92% of the CO2 released from aspartate, whereas oxidation of the inner carbon atoms of aspartate (which occurs beyond the 2-oxoglutarate dehydrogenase step) represented only 8-10% of aspartate carbon oxidation. 3. The formation of [1-14C]glutamine and [1-14C]glutamate from [1-14C]aspartate and [4-14C]aspartate indicated that about one-third of the oxaloacetate synthesized from aspartate underwent randomization at the level of fumarate. 4. With [U-14C]aspartate as substrate, the percentage of the C-1 of glutamate and glutamine found radiolabelled after 60 min of incubation was 92.7% and 47.5% in the absence and the presence of bicarbonate respectively. 5. That CO2 fixation occurred at high rates in the presence of bicarbonate was demonstrated by incubating tubules with aspartate plus [14C]bicarbonate; under this condition, the label fixed was found in C-1 of glutamate, glutamine and aspartate, as well as in C-4 of aspartate, demonstrating not only randomization of aspartate carbon but also aspartate resynthesis secondary to oxaloacetate cycling via phosphoenolpyruvate carboxykinase, pyruvate kinase and pyruvate carboxylase. 6. The importance of CO2 fixation in glutamine synthesis from aspartate is discussed in relation to the possible role of the guinea-pig kidney in systemic acid-base regulation in vivo.

L-649,923, Sodium (βS*, γR*)-4-(3-(4-acetyl-3-hydroxy-2-propylphenoxy)-propylthio)-γ-hydroxy-β-methylbenzenebutanoate, a selective, orally active leukotriene receptor antagonist

1986 ◽  
Vol 64 (8) ◽  
pp. 1068-1075 ◽  
Author(s):  
T. R. Jones ◽  
R. Young ◽  
E. Champion ◽  
L. Charette ◽  
D. Denis ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Competitive Inhibition ◽  
Competitive Inhibitor ◽  
Plot Analysis ◽  
Prostaglandin F ◽  
Leukotriene Receptor ◽  
Orally Active ◽  
Intraduodenal Administration

L-649,923, Sodium (βs*, γR*)-4-(3-(4-acetyi-3-hydroxy-2-propylphenoxy)propylthio)-γ-hydroxy-β-methylbenzenebutanoate is a selective and competitive inhibitor of [3H]leukotriene D4 (Ki value of 400 nM) and to a lesser extent [3H]leukotriene C4 (Ki value of 8.6 μM) binding in guinea-pig lung homogenates. Functionally, it selectively antagonized contractions of guinea pig trachea induced by leukotriene C4, D4, E4, and F4 but not those induced by acetylcholine, histamine, serotonin, prostaglandin F2α, or U-44069 (stable endoperoxide analogue). Schild plot analysis indicated a competitive inhibition of contractions of guinea-pig ileum induced by leukotriene D4 (pA2 8.1) and contractions of guinea-pig trachea induced by leukotrienes E4 and F4 (pA2 7.1 and 6.9, respectively). In contrast, contractions of guinea-pig trachea induced by leukotrienes C4 (pA2 7.2; slope 0.6) and D4 (pA2 7.2; slope 0.7) were inhibited in a noncompetitive fashion. In vivo, intravenously administered L-649,923 selectively blocked bronchoconstriction induced in anesthetized guinea pigs by leukotriene C4 and D4 (ED50 values i.v. 0.38 and 0.26 mg/kg, respectively) but not that induced by histamine, arachidonic acid, serotonin, U-44069, or acetylcholine. Following intraduodenal administration, L-649,923, blocked leukotriene D4 induced bronchoconstriction (5 and 10 mg/kg). The present findings indicate that selective antagonists, such as L-649,923, may be useful for defining the role of leukotrienes in diseases such as bronchial asthma.

Role of platelet-activating factor-acether in mediating guinea pig anaphylaxis

Science ◽  
1986 ◽  
Vol 232 (4746) ◽  
pp. 58-60 ◽  
Author(s):  
H Darius ◽  
DJ Lefer ◽  
JB Smith ◽  
AM Lefer
Keyword(s):  
Guinea Pig ◽  
Platelet Activating Factor ◽  
Respiratory Arrest ◽  
Independent Component ◽  
Systemic Hypotension ◽  
Isolated Lung

The pathophysiology of anaphylaxis is very complex, and the sequelae of events are not fully explained in terms of the effects of histamine and peptide leukotrienes alone. Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, PAF-acether) has been detected in animals undergoing anaphylaxis. Injection of synthetic PAF-acether induces similar effects, including bronchoconstriction, respiratory arrest, systemic hypotension, neutropenia, and thrombocytopenia. The results reported here demonstrate that the histamine- and leukotriene-independent component of guinea pig anaphylaxis in vivo and in isolated lung parenchymal strips in vitro is mediated by PAF-acether. However, PAF-acether is not responsible for the anaphylaxis-induced thrombocytopenia.

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