H-7, A protein kinase C inhibitor, inhibits spontaneous tone and spasmogenic responses in normal and sensitized guinea pig trachea

Abstract

1. 1. H-7, a protein kinase C inhibitor, fully inhibited the spontaneous and stimulated (KC120 mM or histamine 0.5 mM) tone of trachea from normal and sensitized guinea pig. 2. 2. H-7 depressed the concentration-contraction curves to KCI, histamine or 5-hydroxytryptamine in epithelium-denuded, indomethacin-treated, trachea from normal and sensitized guinea pigs while responses to CaCI 2 (in Ca 2+-free, K +-depolarized tissues) and acetylcholine were not affected. 3. 3. H-7 (100 gM) did not depress Ca 2+ (20 μM)-induced contraction of Triton X-100 skinned trachea. 4. 4. These results suggest the involvement of PKC in the maintenance of spontaneous tone and spasmogenic responses of guinea pig trachea.