X Liu1, Y Xu, Z Zhang. 1. Department of Respiratory Medicine, Tongji Hospital, Tongji Medical University, Wuhan 430030.
Abstract
OBJECTIVE: To investigate if the role of protein kinase C(PKC) signal pathway in the regulation of tracheal and lung parenchymal strips tone in normal guinea-pigs is different from that in ovalbumin-sensitized ones. METHOD: By measuring the tones of tracheal and lung parenchymal strips isolated from normal and ovalbumin sensitized guinea-pigs, the effects of PKC-specific activator PMA and inhibitor Ro31-8220 were observed and compared. RESULT: (1) PMA caused concentration-dependent relaxations in the tracheal strips of both normal (n = 7) and sensitized animals(n = 7) and the relaxant effects were significantly stronger on the strips from the sensitized animals than on those from the normal ones(P < 0.05). The relaxing effects could be completely inhibited by Ro31-8220. (2) PMA led to concentration-dependent contractions in the lung parenchymal strips and the contractile effects were significantly stronger on the strips from the sensitized animals (n = 5) than on those(n = 6) from the normal ones (P < 0.05). This contractile response could be abolished by Ro31-8220. (3) Ro31-8220 could partly suppress the contractile response of sensitized lung parenchymal strips to in vitro antigen attacks (n = 10, P < 0.01). CONCLUSION: (1) The regulating effects of PKC on airway smooth muscle tone differ in different locations of the guinea-pig airways. (2) The function of PKC signal pathway in airway smooth muscle from sensitized guinea-pig is increased compared with that from normal one. It is suggested that the role of PKC signal pathway may be important in the pathogenesis of asthma.
OBJECTIVE: To investigate if the role of protein kinase C(PKC) signal pathway in the regulation of tracheal and lung parenchymal strips tone in normal guinea-pigs is different from that in ovalbumin-sensitized ones. METHOD: By measuring the tones of tracheal and lung parenchymal strips isolated from normal and ovalbumin sensitized guinea-pigs, the effects of PKC-specific activator PMA and inhibitor Ro31-8220 were observed and compared. RESULT: (1) PMA caused concentration-dependent relaxations in the tracheal strips of both normal (n = 7) and sensitized animals(n = 7) and the relaxant effects were significantly stronger on the strips from the sensitized animals than on those from the normal ones(P < 0.05). The relaxing effects could be completely inhibited by Ro31-8220. (2) PMA led to concentration-dependent contractions in the lung parenchymal strips and the contractile effects were significantly stronger on the strips from the sensitized animals (n = 5) than on those(n = 6) from the normal ones (P < 0.05). This contractile response could be abolished by Ro31-8220. (3) Ro31-8220 could partly suppress the contractile response of sensitized lung parenchymal strips to in vitro antigen attacks (n = 10, P < 0.01). CONCLUSION: (1) The regulating effects of PKC on airway smooth muscle tone differ in different locations of the guinea-pig airways. (2) The function of PKC signal pathway in airway smooth muscle from sensitized guinea-pig is increased compared with that from normal one. It is suggested that the role of PKC signal pathway may be important in the pathogenesis of asthma.