Probable involvement of kinase C in rat bronchial induced by acetylcholine epsilon - isoform of protein smooth muscle contraction

Although the role of protein kinase C (PKC) has been suggested in agonist-induced bronchial smooth muscle contraction, the PKC isoform(s) involved in this phenomenon is not clear now. In the present study, the effects of three PKC inhibitors, GFI092603X, G66976 and rottlerin on acetylcholine (ACh)-inducecl bronchial smooth inuscle contractien were examined to identify the PKC isoform(s) involved in the contraction. Bronchial smooth muscles were pretreated with each PKC inhibitor (10J6 and 10'5 M) 30 min before cumulative administration of ACh, In another series of experiments, the effeets of PKC inhibitors on the maximal contraction induced by 10'S M ACh were determined: the inhibitors were cumulatively administered (10'S10'" M) after the AChinduced contraction reachecl plateau. The ACh-induced bronchial smooth muscle contraction was significantly inhibited by GFI09203X (inhibitor of PKCct, A T, 6 and a) but not by Gd6976 (PKC5, fi and y inhibitor) and rottlerin (PKC6 and e inhibitor). Moreover, mRNA and protein of PKCE were detected in rat bronchial smooth muscle. Taken together, PKCg might be invelved in the ACh-induced bronchial smooth muscle contraction in rats.