Abstract
BN 50739, a new PAF receptor antagonist, was tested in vitro and in vivo for its capacity to block PAF, endotoxin and recombinant human tumor necrosis factor-alpha (rTNF)-mediated effects. In vitro, BN 50739 blocked PAF-induced platelet aggregation by 60 to 100% at 0.2-1 x 10(-7) M (P less than .002), respectively. In the conscious rat, pretreatment (30 min) with BN 50739 (n = 5-13) dose-dependently attenuated PAF-induced hypotension (-5 +/- 5 vs. - 43 +/- 2 mm Hg, P less than .01) and shortened the recovery time of mean arterial pressure (22 +/- 13 vs. 325 +/- 46 sec, P less than .01). BN 50739 (10 mg/kg i.p., n = 5-11) prevented endotoxin (14.4 mg/kg) induced-hemoconcentration (54 +/- 1 vs. 46 +/- 1%, P less than .01) and reduced 24-hr mortality (100 vs. 60%, P less than .05). Only partial protection was conveyed by BN 50739 against the hypotensive response to endotoxin (115 +/- 3 vs. 91 +/- 4 mm Hg, P less than .03). Also, BN 50739 attenuated the lipopolysaccharide-induced elevation of plasma thromboxane B2 (21.2 +/- 0.8 vs. 46.7 +/- 11.8 pg/100 microliters, P less than .01) and tumor necrosis factor-alpha (7523 +/- 3983 vs. 26,430 +/- 3541 U/ml, P less than .05), whereas leukopenia and thrombocytopenia remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|