The Synergistic Effect of High K+ and Hypoxia on Extracellular Concentrations of Neuroactive Amino Acid in Hippocampus

2000 ◽  
pp. 247-249
Author(s):  
Y. Matsushita ◽  
K. Shima ◽  
H. Katoh ◽  
H. Nawashiro
Keyword(s):  
Amino Acid ◽  
Synergistic Effect ◽  
High K ◽  
Neuroactive Amino Acid

Synergistic effect of citrulline and lactoserum on amino acid availability

2018 ◽  
Vol 37 ◽  
pp. S163
Author(s):  
P. Jegatheesan ◽  
C. Vicente ◽  
P. Marquet De Rouge ◽  
N. Neveux ◽  
R. Ramassamy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Synergistic Effect ◽  
Amino Acid Availability

Epinephrine modifications of insulin release and of 86Rb+ or 45Ca2+ fluxes in rat islets

1983 ◽  
Vol 244 (3) ◽  
pp. E245-E252 ◽  
Author(s):  
T. Tamagawa ◽  
J. C. Henquin
Keyword(s):  
Amino Acid ◽  
Insulin Release ◽  
Maximum Effect ◽  
Rat Islets ◽  
High K ◽  
Net Uptake ◽  
Insulinotropic Effect ◽  
Camp Levels ◽  
K Permeability ◽  
86Rb Influx

The effects of epinephrine on insulin release, 86Rb+ fluxes, and 45Ca2+ fluxes were measured in rat islets. In the presence of 10 mM glucose, epinephrine did not affect 86Rb+ influx and slightly increased net uptake. It caused a monophasic inhibition of release and a biphasic decrease in 86Rb+ efflux. A maximum effect was observed with 1 microM epinephrine, but release was more markedly inhibited by lower concentrations of the catecholamine than was the efflux. Epinephrine inhibition of release and efflux was reversed by phentolamine and yohimbine but not by prazosin or propranolol. It was mimicked by norepinephrine and clonidine. The inhibition of 86Rb+ efflux persisted when insulin release was prevented by omission of extracellular calcium. Ouabain or high K+ markedly increased 86Rb+ efflux in the presence of glucose and epinephrine; theophylline and quinine had a similar but smaller effect. None of these agents restored insulin release. Epinephrine abolished the insulinotropic effect of arginine without altering the rise in 86Rb+ efflux triggered by the amino acid. Epinephrine abolished insulin release but inhibited 45Ca2+ efflux only partially during stimulation by glucose or by barium plus theophylline. The results show that epinephrine does not inhibit insulin release by activating the Na pump or by increasing K permeability of the B cell membrane. On the contrary, the inhibition of release is accompanied by a decrease in 86Rb+ efflux. Both result from activation of alpha 2-receptors but are not causally related; they could be due to remodeling of Ca2+ fluxes and/or changes in cAMP levels.

scholarly journals Characterization and Synergistic Interactions of Fibrobacter succinogenes Glycoside Hydrolases

2007 ◽  
Vol 73 (19) ◽  
pp. 6098-6105 ◽  
Author(s):  
Meng Qi ◽  
Hyun-Sik Jun ◽  
Cecil W. Forsberg
Keyword(s):  
Amino Acid ◽  
Synergistic Effect ◽  
Genome Sequence ◽  
Glycoside Hydrolase ◽  
Amino Acid Sequences ◽  
Glycoside Hydrolases ◽  
Fibrobacter Succinogenes ◽  
Gene Encoding ◽  
Substrate Specificities ◽  
Synergistic Interactions

ABSTRACT The objectives of this study were to characterize Fibrobacter succinogenes glycoside hydrolases from different glycoside hydrolase families and to study their synergistic interactions. The gene encoding a major endoglucanase (endoglucanase 1) of F. succinogenes S85 was identified as cel9B from the genome sequence by reference to internal amino acid sequences of the purified native enzyme. Cel9B and two other glucanases from different families, Cel5H and Cel8B, were cloned and overexpressed, and the proteins were purified and characterized. These proteins in conjunction with two predominant cellulases, Cel10A, a chloride-stimulated cellobiosidase, and Cel51A, formerly known as endoglucanase 2 (or CelF), were assayed in various combinations to assess their synergistic interactions using ball-milled cellulose. The degree of synergism ranged from 0.6 to 3.7. The two predominant endoglucanases produced by F. succinogenes, Cel9B and Cel51A, were shown to have a synergistic effect of up to 1.67. Cel10A showed little synergy in combination with Cel9B and Cel51A. Mixtures containing all the enzymes gave a higher degree of synergism than those containing two or three enzymes, which reflected the complementarity in their modes of action as well as substrate specificities.

Effect of disodiumN,N-dialanyl protoporphyrinate, diarginine protoporphyrinate and diarginineN,N-dialanyl protoporphyrinate on respiratory burst of human neutrophilsin vitro

2010 ◽  
Vol 14 (03) ◽  
pp. 244-251
Author(s):  
Andrzej M. Bugaj ◽  
Hanna Billert ◽  
Patrycja Kołodziejska ◽  
Alina Limaszewska ◽  
Zuzanna Stochmal
Keyword(s):  
Antioxidant Activity ◽  
Photodynamic Therapy ◽  
Amino Acid ◽  
Synergistic Effect ◽  
Respiratory Burst ◽  
Protoporphyrin Ix ◽  
Antioxidant Effect ◽  
Fluence Rate ◽  
Opsonized Zymosan ◽  
Oxidant Effect

The effect of three amino acid protoporphyrin IX (PPIX) derivatives evaluated as sensitizers in photodynamic therapy — disodium N,N -dialanyl protoporphyrinate ( PP(Ala)2Na2), diarginine protoporphyrinate (PPArg2) and diarginine N,N -dialanyl protoporphyrinate (PP(Ala)2Arg2) – non-irradiated and pre-irradiated with UV-A, on respiratory burst of non-stimulated and opsonized zymosan stimulated neutrophils was studied. A potential synergistic effect of diazepam (7-chloro-1-methyl-5-phenyl-1,3-dihydro-2H-1,4-benzodiazepin-2-one) was also examined. PP(Ala)2Na2showed strong pro-oxidant effect towards non-stimulated neutrophils, while PPArg2and PP(Ala)2Arg2revealed no significant effect. In the case of stimulated neutrophils all studied porphyrins showed antioxidant effect, although for PP(Ala)2Na2this effect was significantly weaker than that of PPArg2and PP(Ala)2Arg2. After pre-irradiation with UV-A (λ = 365 nm, fluence 2.0 J.cm-2, fluence rate 6.7 mW.cm-2) the antioxidant activity of all studied sensitizers towards non-stimulated granulocytes did not change significantly when compared to effects of non-irradiated porphyrins, while in the case of stimulated cells, only PPArg2caused significant decrease of respiratory burst. Non-irradiated diazepam showed significant antioxidant effect and enhanced antioxidant effect of all studied porphyrins towards stimulated neutrophils, while after UV-A pre-irradiation it revealed no significant antioxidant effect on non-stimulated and stimulated neutrophils, both alone and in combination with porphyrin sensitizers.

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