The probable involvement of arachidonic acid metabolites in the stimulation of protein synthesis in stretched skeletal muscle in vitro

1983 ◽  
Vol 11 (2) ◽  
pp. 182-183
Author(s):  
RONALD H. SMITH ◽  
ROBERT M. PALMER ◽  
PETER J. REEDS
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Arachidonic Acid ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites ◽  
Stimulation Of

Arachidonic acid metabolites induced β-adrenoceptor densitization in rat lung in vitro

1985 ◽  
Vol 30 (5) ◽  
pp. 799-809 ◽  
Author(s):  
Luisa Daffonchio ◽  
Maria Pia Abbracchio ◽  
Alicia Hernandez ◽  
Emanuela Giani ◽  
Flaminio Cattabeni ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Rat Lung ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites

Microbubble-Induced Phospholipase C Activation Does not Correlate with Platelet Aggregation

1993 ◽  
Vol 69 (04) ◽  
pp. 394-396 ◽  
Author(s):  
R Malmgren ◽  
T Thorsen ◽  
A Nordvik ◽  
H Holmsen
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Phosphatidic Acid ◽  
Phospholipase C ◽  
Human Platelets ◽  
Similar Extent ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites ◽  
Rule Out ◽  
Stimulation Of

SummaryThe effect of nitrogen-(N2-)microbubbles on platelets resembles that of common platelet agonists with respect to aggregation and secretion, but is considerably slower and is poorly inhibited by aspirin. This paper reports the effect of microbubbles on platelet phospholipase C activity in gelfiltered human platelets prelabelled with [32P]Pi ([32P]-GFP). The experiments were run in the presence of an ADP scavenging system in order to rule out effects of ADP. Stimulation of [32P]-GFP for 30 min with microbubbles caused a significant reduction in single platelets (p <0.0004) and a significant increase in 32P-activity in the phosphatidic acid (PA) fraction (p <0.02). Epinephrine potentiated the microbubble-induced reduction in single platelets (p <0.05), but did not enhance the amount of 32P in the platelet [32P]PA fraction. The 32P-radioactivity in the PI-fraction increased with time to a similar extent when [32P]-GFP was stirred for 30 min in absence of microbubbles as it did after 30 min of agonist exposure. There were no significant changes in the [32P]PIP and [32P]PIP2 fractions. Aspirin abolished the microbubble-induced increase in 32P-activity in the PA fraction, but had no significant effect on the reduction in single platelets. Aspirin had a small but significant, reducing effect on platelet aggregation induced by a combination of epinephrine and microbubbles (p <0.05). With epinephrine, however, aspirin did not completely abolish the increase in [32P]-PA. It is concluded that microbubbles alone cause platelets to aggregate by a novel mechanism that operates independent of cyclooxygenase-dependent arachidonic acid metabolites and phospholipase C activation.

Effect of Lipoxygenase Inhibition on Mucous Glycoprotein Secretion from Chinchilla Middle Ear Fpithelial Cells in Vitro

1996 ◽  
Vol 105 (11) ◽  
pp. 916-921 ◽  
Author(s):  
Jizhen Lin ◽  
Youngki Kim ◽  
Frank Ondrey ◽  
Chris Lees ◽  
Steven K. Juhn
Keyword(s):  
Arachidonic Acid ◽  
Epithelial Cells ◽  
Middle Ear ◽  
Platelet Activating Factor ◽  
Lipoxygenase Inhibitor ◽  
Lipoxygenase Inhibition ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites ◽  
Glycoprotein Secretion

Lipoxygenase is an enzyme that metabolizes arachidonic acid down to leukotrienes. Recent studies have shown that the enzyme is implicated in mucous glycoprotein (MGP) secretion stimulated by inflammatory mediators in the airways, suggesting its possible role in secretion of MGP from middle ear epithelial cells. To investigate a correlation between MGP secretion and the arachidonic acid metabolites, we examined the effects of nordihydroguaretic acid (NDGA, both a cyclooxygenase and lipoxygenase inhibitor), low-dose indomethacin (an inhibitor of cyclooxygenase), and A63162 (an inhibitor of lipoxygenase) on MGP secretion in cultured chinchilla middle ear epithelial cells. It was found that lipoxygenase inhibition led to reduction of MGP secretion from cultured chinchilla middle ear epithelial cells, while cyclooxygenase inhibition did not. Both cyclooxygenase and lipoxygenase inhibition resulted in profound blockage of MGP secretion in baseline and platelet activating factor-stimulated MGP secretion. It was concluded, therefore, that MGP secretion was linked to arachidonic acid metabolites, especially lipoxygenase products.

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