Responses to adenosine of isolated transverse or spiral strips of sensitized guinea pig trachea: role of epithelium
Abstract
Aim: To determine the role of the epithelium in the responses to adenosine of isolated trachea from ovalbumin-sensitized guinea pigs.
Methods: Spirally cut tracheal preparations were superfused or immersed in organ baths and transversely cut strips were immersed. Epithelium was removed mechanically from some strips and confirmed by histological examination of a random sample. Tissues were from unsensitized or ovalbumin-sensitized guinea pigs. Isometric tension was measured and responses to adenosine recorded.
Results: In sensitized tissues, contractile responses to adenosine were evident as contractions of superfused spirals or as rightwards shift of the concentration-response curve compared with non-sensitized immersed spirals. Epithelium removal potentiated relaxation responses in both non-sensitized and sensitized strips indicating release of contractile mediators in both tissues. Dipyridamole potentiated relaxation responses in sensitized tissues with and without epithelium.
Conclusion: Sensitization reveals a contractile response to adenosine. The epithelium is not involved in this contractile response nor is it the major site of uptake of adenosine in both sensitized and non-sensitized tissues.
Keywords:
Methods: Spirally cut tracheal preparations were superfused or immersed in organ baths and transversely cut strips were immersed. Epithelium was removed mechanically from some strips and confirmed by histological examination of a random sample. Tissues were from unsensitized or ovalbumin-sensitized guinea pigs. Isometric tension was measured and responses to adenosine recorded.
Results: In sensitized tissues, contractile responses to adenosine were evident as contractions of superfused spirals or as rightwards shift of the concentration-response curve compared with non-sensitized immersed spirals. Epithelium removal potentiated relaxation responses in both non-sensitized and sensitized strips indicating release of contractile mediators in both tissues. Dipyridamole potentiated relaxation responses in sensitized tissues with and without epithelium.
Conclusion: Sensitization reveals a contractile response to adenosine. The epithelium is not involved in this contractile response nor is it the major site of uptake of adenosine in both sensitized and non-sensitized tissues.