The bronchodilator effects of Roflumilast “a selective phosphodiesterase type-4 (PDE4)” inhibitor studied in this experimental protocol. The spiral strips of isolated guinea-pig tracheal chains mounted in organ bath and maintained in Krebs solution ventilated with carbogen at 32 °C and in Ca⁺⁺ restricted krebs solution. PDE inhibitory activity was evaluated by recording dose response curves using inhibitory effect of isoprenaline on CCh induced contractions. For confirmation of PDE inhibition the intracellular cAMP levels were also estimated. Roflumilast resulted a sharp inhibition in contractile responses of carbachol (CCh, 1 µM) and K⁺ (80 mM) and the results were almost similar to verapamil. In Ca⁺⁺ restricted Krebs solution, a rightward shift in the Ca⁺⁺ response curves observed in the tracheal chain strips which were pretreated with Roflumilast (0.001–0.003 mg/mL) and the maximum response was suppressed, similarly as with verapamil. PDE inhibitory effect of Roflumilast evaluated by recording dose-dependent (0.03–0.1 mg/mL) responses, the isoprenaline-induced inhibitory dose response curves shifted leftward similar to papaverine (PDE inhibitor). Pretreatment with Roflumilast exhibited elevated intracellular cAMP levels in tracheal strips. Findings of the experiment conclude bronchodilatory influence of Roflumilast via PDE and Ca⁺⁺ channel inhibition. Results of current experiment offers comprehensive mechanistic background of Roflumilast in future as therapeutic bronchodilator for hyperactive bronchial airway diseases.

在该实验方案中研究了罗氟司特“一种选择性磷酸二酯酶4型（PDE4）”抑制剂的支气管扩张作用。分离的豚鼠气管链的螺旋状条带安装在器官浴中，并保持在32℃下用碳素通气的Krebs溶液和Ca ⁺⁺限制的Krebs溶液中。通过记录剂量反应曲线，使用异丙肾上腺素对CCh诱导的收缩的抑制作用来评估PDE抑制活性。为了证实PDE抑制，还估计了细胞内cAMP水平。罗氟司特对卡巴胆碱（CCh，1 µM）和K ⁺（80 mM）的收缩反应产生了明显的抑制作用，其结果几乎与维拉帕米相似。在Ca ⁺⁺受限Krebs解中，Ca向右移动在用Roflumilast（0.001–0.003 mg / mL）预处理的气管链条中观察到⁺⁺响应曲线，与维拉帕米相似，最大响应得到抑制。罗氟司特的PDE抑制作用通过记录剂量依赖性（0.03-0.1 mg / mL）反应来评估，异丙肾上腺素诱导的抑制剂量反应曲线向左移动，类似于罂粟碱（PDE抑制剂）。罗氟司特预处理在气管带中显示升高的细胞内cAMP水平。实验发现，罗氟司特可通过PDE和Ca ⁺⁺通道抑制作用来支气管扩张作用。目前的实验结果提供了罗氟司特作为治疗支气管扩张性多发性支气管疾病的未来的综合机理背景。