H-7, A PROTEIN-KINASE-C INHIBITOR, INHIBITS SPONTANEOUS TONE AND SPASMOGENIC RESPONSES IN NORMAL AND SENSITIZED GUINEA-PIG TRACHEA

1. H-7, a protein kinase C inhibitor, fully inhibited the spontaneous and stimulated (KCl 20 mM or histamine 0.5 mM) tone of trachea from no rmal and sensitized guinea pig. 2. H-7 depressed the concentration-con traction curves to KCl, histamine or 5-hydroxytryptamine in epithelium -denuded, indomethacin-treated, trachea from normal and sensitized gui nea pigs while responses to CaCl2 (in Ca2+-free K+-depolarized tissues ) and acetylcholine were not affected. 3. H-7 (100 mu M) did not depre ss C2+ (20 mu M)-induced contraction of Triton X-100 skinned trachea. 4. These results suggest the involvement of PKC in the maintenance of spontaneous lone and spasmogenic responses of guinea pig trachea.