Endothelin-1-induced arachidonic acid release by cytosolic phospholipase A2 activation in rat vascular smooth muscle via extracellular signal-regulated kinases pathway.
The present study investigates whether endothelin-1 (ET-1), like noradrenaline (NA), stimulates the release of arachidonic acid (AA) via cytosolic phospholipase A2 (cPLA2) in rat tail artery. In tail artery segments labelled with [3H]AA, ET-1-induced AA release in a concentration-dependent manner with an EC50 of 1.3 nM. The effect of ET-1 was inhibited by bosentan and was insensitive to BQ788, suggesting the involvement of ETA receptor. The stimulation of AA release induced by ET-1 was prevented by arachydonyl trifluoromethyl ketone (AACOCF3), a selective inhibitor of cPLA2 and not by RHC80267, a diacylglycerol lipase inhibitor. Furthermore, PD98059, inhibitor of mitogen-activated protein kinase kinase (MEK) cascade and calphostin C, a protein kinase C (PKC) inhibitor, prevented the stimulation of AA release induced by ET-1 and NA. Immunoblotting of the cytosolic fraction of rat tail arteries stimulated with ET-1 or NA showed an increase in extracellular signal-regulated kinases (ERKs) phosphorylation and this effect was abolished by calphostin C treatment. These findings show that in rat tail artery ET-1 and NA induce a sequential activation of protein kinase C and extracellular signal-regulated kinases that results in stimulation of AA release via cPLA2 activation. This may represent a general pathway by which G-proteins coupled receptors stimulate AA release and its metabolites in vascular smooth muscle.
Trevisi
Lucia
L
Department of Pharmacology and Anaesthesiology, University of Padua, Largo E. Meneghetti 2, 35131, Padua, Italy.
Bova
Sergio
S
Cargnelli
Gabriella
G
Ceolotto
Giulio
G
Luciani
Sisto
S
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D001095:Arachidonic Acids / Q000494:pharmacology; D001158:Arteries; D002352:Carrier Proteins / Q000494:pharmacology; D003512:Cyclohexanones / Q000494:pharmacology; D004347:Drug Interactions; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009638:Norepinephrine / Q000494:pharmacology; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D013623:Tail; D014316:Tritium
D001095:Arachidonic Acids; D002352:Carrier Proteins; D003512:Cyclohexanones; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; C015482:protein kinase modulator; C081565:arachidonyltrifluoromethane; D014316:Tritium; D016718:Arachidonic Acid; C036535:1,6-bis(cyclohexyloximinocarbonyl)hexane; D020928:Mitogen-Activated Protein Kinases; D010741:Phospholipases A; D054467:Phospholipases A2; D009638:Norepinephrine