Prostaglandin D2 (
PGD2) and the selective DP receptor agonist
BW 245C have been previously shown to lower intraocular pressure in rabbits, while
PGD2, but not
BW 245C, caused plasma extravasation, eosinophil infiltration, and goblet cell depletion. In these present studies definition of the ocular pharmacology of
prostaglandin D2 (
PGD2) has been extended by using a further selective DP receptor agonist
SQ 27986 and a potent and selective DP receptor antagonist
BW A868C. In cats and rabbits
SQ 27986 caused
ocular hypotension. The ocular hypotensive effect of
PGD2 in rabbits was blocked by pretreatment with the DP receptor antagonist
BW A868C, whereas the activities of
PGE2 and
PGF2 alpha remained unaltered. The singular involvement of the DP receptor in changes in rabbit intraocular pressure evoked by
PGD2 was thereby verified by using the antagonist
BW A868C. In terms of effects on the ocular surface,
SQ 27986 caused no increase in conjunctival microvascular permeability, no eosinophil infiltration, and no depletion of the goblet cell population. These findings reinforce the concept that selective DP receptor agonists may be useful for lowering intraocular pressure without causing ocular surface pathology.
PGD2 induced increases in conjunctival microvascular permeability were inhibited by
BW A868C, despite the fact that DP receptor agonists failed to evoke a plasma exudation response. This finding was unexpected and suggests a possible subdivision of the DP receptor designation.