[Thromboxane A2 could be involved in bronchial hyperresponsiveness to methacholine in asthmatic subjects but not in bronchitic subjects].
To determine whether the involvement of thromboxane A2 in bronchial hyperresponsiveness is specific to asthma, we examined the effects of a selective thromboxane synthetase inhibitor (OKY-046) and a cyclooxygenase inhibitor (indomethacin) on bronchial responsiveness to methacholine in patients with bronchial asthma and chronic bronchitis. The provocative concentration of methacholine producing a 20% fall in forced expiratory volume in one second (PC20-FEV1) was measured before and after oral administration of OKY-046 and indomethacin in eight asthmatic and 10 bronchitic subjects. Baseline FEV1 value was not altered by OKY-046 or indomethacin. The geometric mean value of PC20-FEV1 increased significantly (p less than 0.005) from 1.78 to 4.27 mg/ml after OKY-046 in asthmatic subjects, but not in bronchitic subjects. On the other hand, PC20-FEV1 was not altered by indomethacin in all subjects. It was concluded that the involvement of thromboxane A2 in bronchial hyperresponsiveness may be specific to asthma.
Fujimura
M
M
Third Department of Internal Medicine, Kanazawa University School of Medicine, Japan.
Sakamoto
S
S
Kamio
Y
Y
Nishi
K
K
Saito
M
M
Miyake
Y
Y
Nomura
M
M
Matsuda
T
T
D001249:Asthma / Q000378:metabolism*; D001980:Bronchi / Q000187:drug effects*; D001985:Bronchial Provocation Tests; D001991:Bronchitis / Q000378:metabolism*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008688:Methacholine Compounds; D008689:Methacrylates; D008875:Middle Aged; D013928:Thromboxane A2 / Q000502:physiology*; D013930:Thromboxane-A Synthase / Q000037:antagonists & inhibitors
D008688:Methacholine Compounds; D008689:Methacrylates; D016210:Methacholine Chloride; D013928:Thromboxane A2; D013930:Thromboxane-A Synthase; C034364:ozagrel