感作ウサギの過換気誘発気道収縮(HIB)に対するβ_2刺激薬,DSCG,抗コリン薬の効果 [in Japanese] Effects of a β_2-agonist, Sodium Cromoglycate, and an Anticholinergic Agent on Hyperventilation-induced Bronchoconstriction in Sensitized Rabbits [in Japanese]
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我々は感作ウサギが過換気負荷により気道収縮 (HIB) をおこすことを報告してきた. 今回我々は, 抗コリン薬, β<sub>2</sub>刺激薬, DSCGを前投与し, その効果からHIBのメカニズムを検討した. 卵白アルブミンで感作した日本白色ウサギ (n=21) を麻酔後, 気管切開し, 機械換気を行った. 1群: コントロール (n=7), 2群: Procaterol 50μg/ml (n=4), 3群: DSCG 10mg/ml (n=4), 4群: Ipratropium 1mg/ml (n=6) に分け, 各薬剤を1分間吸入させた後, 過換気負荷 (5%CO<sub>2</sub>を含む混合気で1回換気量: 7ml/kg, 換気回数: 120/分) を行った. 負荷前, 直後, 5, 15, 30分後にR<sub>L</sub>, Cdyn を測定し, 負荷前に対する%変化率 (%R<sub>L</sub>, %Cdyn) をもとめた. %R<sub>L</sub> (平均値) は, 5分後に1群+49%, 2群-6%, 3群+23%, 4群+1%と, 2, 4群で, 15分後に3群でもHIBの抑制を認めた. これらのことよりHIBには, 気道平滑筋の収縮が関与して, その機序としては迷走神経系, chemical mediator の関与が考えられた.
Hyperventilation can induce bronchoconstriction in ovalbumin-sensitized rabbits. To investigate the roles of the β-receptor parasympathetic nervous system and of chemical mediators in hyperventilation-induced bronchoconstriction (HIB), the effects of a β<sub>2</sub>-agonist, of sodium cromoglycate, and of an anticholinergic agent on HIB were studied. Rabbits were divided to four groups and treated as follows. Group 1: Control (n=7, 0.9% saline); Group 2: Procaterol (n=4, 50μg/l); Group 3: Sodium cromoglycate (n=4, 10mg/ml); and Group 4: Ipratropium bromide (n=6, 1mg/ml). Each drug was inhaled for 1min via an ultrasonic nebulizer. Then, for the eucapnic hyperventilation challenge, sensitized rabbits were mechanically hyperventilated for 15min (120 breaths/min, tidal volume=7ml/kg) with dry air containing 5% CO<sub>2</sub> at room temperature. Total lung resistance and dynamic compliance were measured before, and 0. 5, 15, and 30min after hyperventilation. The mean percent change in resistance measured 5min after the hyperventilation was +49% in group 1, -6% in group 2, +23% in group 3, and +10 in group 4. The changes in groups 2 and 4 were significantly less than in group 1 (p<0.05).<br>In conclusion, HIB is mainly caused by bronchial smooth muscle constriction, and chemical mediators and the parasympathetic nervous system may play important roles in the development of HIB in sensitized rabbits.
- The Japanese journal of thoracic diseases
The Japanese journal of thoracic diseases 33(8), 856-861, 1995-08-25
The Japanese Respiratory Society