[Effect of saibokuto on mucociliary transport system in the airway--basic and clinical assessments]

We studied the effects of Saibokuto, an antiasthmatic agent, on the airway mucociliary transport system. The addition of Saibokuto to a Rose chamber containing rabbit cultured tracheal epithelium dose-dependently increased ciliary beat frequency (CBF) as assessed by a photoelectric method: the maximal increase from the baseline value was 31.5 +/- 5.2% (p less than 0.001) and the concentration of Saibokuto required to produce a half-maximal effect (EC50) was 10(-4) mg/ml. This effect was not affected by the beta-adrenergic receptor antagonist propranolol or Ca(2+)-free medium, but was inhibited by the cyclooxygenase inhibitor indomethacin. Intracellular cyclic AMP levels were increased from 45.6 +/- 8.2 to 72.1 +/- 12.6 pmole/mg protein by 1.0 mg/ml Saibokuto (p less than 0.05). Thus, Saibokuto enhances ciliary motility probably through the synthesis of cyclooxygenase products and cyclic AMP. Additionally, administration of this drug to patients with chronic bronchitis, asthma and bronchiectasis improved their problems with sputum expectoration and reduced the amount of daily sputum (p less than 0.001). Therefore, Saibokuto may be of value in the treatment of patients with impaired mucociliary transport function in the airway.