Effects of Anti-Asthma Drugs and Potassium Channel Openers on Neurally-Mediated Contraction of Isolated Guinea Pig Trachea

The effects of anti-asthma drugs, isoproterenol, aminophylline and hydrocortisone, and potassium channel openers on the contraction induced by electrical stimulation or exogenously applied acetylcholine were investigated in isolated guinea pig trachea. Isoproterenol and aminophylline non-selectively inhibited both the contraction evoked by vagus nerve- and that by transmural field-stimulation, but had no effect on the response induced by exogenously applied acetylcholine. Hydrocortisone and potassium channel openers, NIP-121 and cromakalim, preferentially inhibited vagus nerve-mediated response. These results suggest that anti-asthma drugs may have an ability to inhibit neurally-mediated contraction in the guinea pig trachea.