The effect of BAY u 3405, a thromboxane receptor antagonist, on prostaglandin D2-induced nasal blockage.
BACKGROUND
Nasal lavage and challenge studies in allergic rhinitis implicate prostaglandin (PG) D2 in the genesis of nasal blockage. PG D2 is known to act via at least two receptors, the thromboxane prostanoid receptor and the PG D2 prostanoid (DP) receptor; the lower airway effects are mediated chiefly by the TP receptor. The receptor involved in the genesis of PG D2-induced nasal blockage is unknown. BAY u 3405 is a potent selective competitive TP receptor antagonist, which inhibits the lower airway response to PG D2, and shifts the dose-response curve to the right by up to 16-fold.


METHODS
The efficacy of a single oral dose of 20 mg of BAY u 3405 was examined in comparison with PG D2 nasal insufflation in a randomized, double-blind, placebo-controlled crossover study, with objective measurement of nasal resistance by active posterior rhinomanometry.


RESULTS
BAY u 3405 afforded no protection against PG D2-induced nasal blockage.


CONCLUSIONS
This suggests that PG D2-induced nasal blockage may be mediated by the DP receptor rather than the TP receptor and that TP receptor antagonists are unlikely to be of benefit in the treatment of allergic rhinitis. In vivo investigation with specific potent DP receptor antagonists is awaited.
Johnston
S L
SL
Immunopharmacology Group, Southampton General Hospital, UK.
Smith
S
S
Harrison
J
J
Ritter
W
W
Howarth
P H
PH
D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000187:drug effects; D002227:Carbazoles / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D008875:Middle Aged; D009299:Nasal Provocation Tests; D009666:Nose / Q000187:drug effects*; D015230:Prostaglandin D2 / Q000494:pharmacology*; D017482:Receptors, Thromboxane / Q000037:antagonists & inhibitors*; D012221:Rhinitis, Allergic, Perennial / Q000188:drug therapy* / Q000503:physiopathology; D013449:Sulfonamides / Q000494:pharmacology* / Q000627:therapeutic use
D002227:Carbazoles; D017482:Receptors, Thromboxane; D013449:Sulfonamides; C063119:ramatroban; D015230:Prostaglandin D2