The effects of
ICI 185,282 (5(Z)-7-([ 2,4,5-cis]-4-O-hydroxyphenyl-2-trifluoromethyl-1, 3-
dioxan-5-yl)heptenoic
acid) have been studied on guinea-pig platelets and pulmonary smooth muscle in-vitro and in-vivo. When tested on guinea-pig lung parenchyma in-vitro.
ICI 185,282 (1 x 10(-7) M) produced a significant shift in
U-46619 response curves (concentration ratio of 13:3); the antagonist (1 x 10(-5) M) did not modify
histamine responses. When tested on guinea-pig trachea in-vitro
ICI 185,282 (1 x 10(-7) M) caused significant inhibition of
U-46619 and
PGD2 responses (concentration ratios of 8.3 and 14.1, respectively); the antagonist (1 x 10(-5) M proved less effective against contractions of
PGF2 alpha,
LTD4 and
histamine (concentration ratios of 7.0, 1.5 and 1.6). When added to guinea-pig platelet rich plasma in-vitro,
ICI 185,282 (x 10(-6), 1 x 10(-5) M) caused concentration-dependent parallel shifts to the right of
U-46619 aggregation curves, yielding concentration ratios of 13.6 and 141.9, respectively. In-vitro, addition of
ICI 185,282 (x 10(-5) M) to
indomethacin-treated pulmonary smooth muscle did not modify resting tone, neither did it induce aggregation or swelling in platelet-rich plasma preparations. When administered orally to guinea-pigs
ICI 185,282 (0.1, 0.5 mg kg-1) caused a significant inhibition of
U-46619-induced platelet aggregation ex-vivo which persisted greater than or equal to 8 h. In-vivo, a single oral dose of
ICI 185,282 (1 mg kg-1) inhibited
bronchospasm induced by
U-46619,
PGD2,
PGF2 alpha,
arachidonic acid,
LTD4 and PAF; responses to
histamine were unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)