thromboxane-b2 and 1-((4-5-bis(4-methoxyphenyl)-2-thiazoyl)carbonyl)-4-methylpiperazine

The contribution of cycloxygenase (COX)-1 and COX-2 in antigen-induced release of mediators and ensuing bronchoconstriction was investigated in the isolated perfused guinea pig lung (IPL). Antigen challenge with ovalbumin (OVA) of lungs from actively sensitised animals induced release of thromboxane (TX)A(2), prostaglandin (PG)D(2), PGF(2)(alpha), PGI(2) and PGE(2), measured in the lung effluent as immunoreactive TXB(2), PGD(2)-MOX, PGF(2)(alpha), 6-keto PGF(1)(alpha) and PGE(2), respectively. This release was abolished by the non-selective COX inhibitor flurbiprofen (10 microM). In contrast, neither the selective COX-1 inhibitor FR122047 nor the selective COX-2 inhibitor celecoxib (10 microM each) significantly inhibited the OVA-induced bronchoconstriction or release of COX products, except for PGD(2). Another non-selective COX inhibitor, diclofenac (10 microM) also significantly inhibited antigen-induced bronchoconstriction. The data suggest that both COX isoenzymes, COX-1 and COX-2 contribute to the immediate antigen-induced generation of prostanoids in IPL and that the COX-1 and COX-2 activities are not associated with different profiles of prostanoid end products.

Topics: Animals; Bronchoconstriction; Celecoxib; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Diclofenac; Flurbiprofen; Guinea Pigs; Humans; Leukotrienes; Lung; Male; Ovalbumin; Piperazines; Prostaglandins; Pyrazoles; Sulfonamides; Thiazoles; Thromboxane A2; Thromboxane B2

We investigated the effects of FR122047 (1-[(4,5-bis(4-methoxyphenyl)-2-thiazoyl)carbonyl]-4-methylpiperazine hydrochloride), a selective cyclo-oxygenase (COX)-1 inhibitor, in rat type II collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA). Using an ex vivo rat whole blood assay, FR122047 (0.032 - 3.2 mg kg(-1)) inhibited COX-1-derived thromboxane (TX) B(2) production with ED(50) value of 0.059 mg kg(-1), indicating that it was orally active, but did not inhibit lipopolysaccharide-induced prostaglandin (PG) E(2) production derived by COX-2. Oral administration of FR122047 showed a dose-dependent anti-inflammatory effect in rat CIA with ED(50) value of 0.56 mg kg(-1). This drug also dose dependently suppressed the levels of PGE(2) and TXB(2) in CIA rat paws with ED(50) values of 0.24 and 0.13 mg kg(-1), respectively. FR122047 had no effect in rat AIA model. In contrast, indomethacin, a non-selective COX inhibitor, was anti-inflammatory and reduced the formation of PGs in AIA rat paws. Unlike indomethacin, chronic treatment of FR122047 did not damage the stomach mucosa in CIA rats. These results demonstrate that COX-1 contributes to the oedema and the formation of PGE(2) and TXB(2) in rat CIA model, but not in rat AIA model. We conclude that FR122047 has an orally active and anti-inflammatory effect mediated by inhibition of PGE(2) and TXB(2) produced by COX-1 at a site of inflammation induced by type II collagen and it may be a useful tool for studying the involvement of COX-1 in various in vivo models of inflammation.

Topics: Adjuvants, Immunologic; Animals; Arthritis, Experimental; Chronic Disease; Collagen; Cyclooxygenase 1; Cyclooxygenase Inhibitors; Dinoprostone; Dose-Response Relationship, Drug; Edema; Female; Hindlimb; Isoenzymes; Membrane Proteins; Piperazines; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Inbred Lew; Thiazoles; Thromboxane B2