Effects of β-Adrenoceptor Agonists on Airway Smooth Muscle and on Slow-contracting Skeletal Muscle: In Vitro and In Vivo Results Compared

Abstract

Ten .beta.-adrenoceptor agonists [epinephrine bitartrate, isoprenaline hydrochloride, tert butyl norepinephrine acetate, protokylol hydrochloride, orciprenaline sulfate, terbutaline sulfate, D2131 [1-(3,5-dihydroxyphenyl)-2[1,1-dimethyl-2-hydroxyethyl)-amino]ethanol sulfate], fenoterol hydrochloride, D2084 [1-(3,5-dihydroxyphenyl)-2-[(1-methyl-2-(3,4-metylenedioxyphenyl)-ethylamino]ethanol hydrochloride] and salbutamol] were examined with respect to relaxation of pilocarpine-contracted trachea and depression of contractions of the soleus muscle of the guinea-pig in vitro and counteraction of histamine-induced bronchospasm and depression of contractions of the soleus muscle of the cat in vivo. There was a close correlation between the results obtained in vitro and results obtained on the corresponding tissues in vivo in spite of the different species used. A close correlation was also observed between effects on airway smooth muscle and on the soleus muscle contractions in vitro as well as in vivo for all compounds examined.