[Effect of thromboxane receptor antagonist, BAY u 3405 on the late phase pulmonary response in guinea pigs].
The effect of the specific thromboxane (Tx)A2 receptor antagonist, BAY u 3405 on the late asthmatic response (LAR) was investigated in guinea pigs which are sensitized actively with Ascaris suum antigen. Respiratory resistance (Rrs) of awake guinea pigs was measured by 30 Hz oscillation method for 6 hours after antigen challenge. %Rrs was calculated as the increase rate of Rrs to baseline Rrs (pre-challenge value). Ten mg/kg of BAY u 3405 or vehicle (0.5% methyl cellulose) was administered orally after the end of immediate asthmatic response, i.e., 2 hours after antigen challenge. %Rrs of the control group at 4 and 5 hours after antigen challenge were 101.4 +/- 27.5% and 77.5 +/- 19.9%, respectively. Those of the BAY group were 32.5 +/- 6.2% and 23.5 +/- 5.0%, respectively. %Rrs of the BAY group were significantly lower than those of the control group at both timings (p < 0.05). No significant difference was shown between the BAY group and the control group in the results of the bronchoalveolar lavage (BAL) 4 hours after challenge. Concerning the results of BAL at 6 hours after challenge, the total cell count and its segment, eosinophils count and lymphocytes count in the BAY group were 274.9 +/- 70.5, 62.5 +/- 13.1, 11.3 +/- 3.3 (x 10(5) cells), respectively, resulting in significantly smaller numbers (each p < 0.05) than those in the control group which were 491.9 +/- 55.1, 198.6 +/- 43.9, 32.1 +/- 7.3 (x 10(5) cells), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
First Department of Internal Medicine, Tohoku University School of Medicine.
H
H
Inoue
N
N
Tani
H
H
Iijima
A
A
Igarashi
S
S
Okada
T
T
Takishima
D000403:Airway Resistance / Q000187:drug effects*; D000818:Animals; D001249:Asthma / Q000276:immunology* / Q000473:pathology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002227:Carbazoles / Q000494:pharmacology*; D006168:Guinea Pigs; D007958:Leukocyte Count; D008168:Lung / Q000187:drug effects*; D008297:Male; D017482:Receptors, Thromboxane / Q000037:antagonists & inhibitors*; D013449:Sulfonamides / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000502:physiology
D002227:Carbazoles; D017482:Receptors, Thromboxane; D013449:Sulfonamides; D013928:Thromboxane A2; C063119:ramatroban