The 'in vivo' and 'ex vivo' roles of cyclooxygenase-2, nuclear factor-κB and protein kinases pathways in the up-regulation of B1 receptor-mediated contraction of the rabbit aorta

This study investigates some of the mechanisms involved in the up-regulation of the B-1 receptor in the rabbit aorta. Pre-treatment of rabbit aorta with cyclooxygenase (COX) inhibitors 5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsuphonyl) phenyl-2 (5H)-furanone (DFU), N-[2-cyclohexyloxy-4-nitrophenyl] methanesulfonamide (NS-398) or with indomethacin, but not with piroxicam, for 6 h, resulted in a significant inhibition of time-dependent contraction to the B-1 selective agonist des-Arg(9)-Bradykinin (des-Arg(9)-BK), without affecting noradrenaline (NA) response. The kinase inhibitors bisindoylmaleimidine IX (RO 318220), staurosporine, genistein or tyrphostin B42 and the nuclear factor-kappaB (NF-kappaB) inhibitors pyrrolidinedithiocarbamate (PDTC), N-alpha-p-tosyl-L-lysine chloro-methyl ketone (TLCK) or sulfasalazine, incubated for 6 h each, resulted in similar inhibition of des-Arg(9)-BK-induced contraction. When these inhibitors were pre-incubated for only 30 min, 6 h after setting up the preparations, sulfasalazine was the only drug tested that inhibited des-Arg(9)-BK-induced contraction, an effect which was reverted after the washing-out of the preparations. In preparations obtained from animals treated with lipopolysaccharide i.v. (LPS) 12 h prior, the up-regulation of B-1 receptor in the aorta was markedly increased. The treatment of rabbits with PDTC, dexamethasone (Dexa), genistein or an association of subliminal doses of Dexa or with PDTC 12 h prior, which alone had no effect, all caused significant inhibition of des-Arg(9)-BK-induced contraction in the rabbit aorta. These results indicate that the time-dependent up-regulation of des-Arg(9)-BK-mediated contraction in the rabbit aorta involves the activation of protein kinase C, tyrosine kinase, through participation of COX-2 and the NF-kappaB transcription factor pathways. (C) 2001 Elsevier Science B.V. All rights reserved.