Endothelin-1 expression during early response after antigen challenge in brown-norway rats

The objective of this study is to investigate if endothelin-1 (ET-1) gene expression changes during the early response phase following antigen challenge. We used sensitized Brown-Norway rats known to develop an early airway response after antigen challenge. After ovalbumin challenge, sensitized rats presented an early response, characterized by an increase in pulmonary pressure (209+/-14.53%,P<0. 01) and diminished functional parameters (inspiratory capacity, forced vital capacity (FVC) and expiratory flow at 75% of FVC), compared to their respective basal values. ET-1 mRNA expression was assessed by reverse transcription and polymerase chain reaction using specific primers for prepro-ET-1. A group of unsensitized rats was used as control. ET-1 expression was significantly enhanced in sensitized rats during the early response (290+/-62%,P<0.01) compared to the control group. In conclusion, antigen challenge induces an activation of ET-1 gene expression during the early response in Brown-Norway rats, suggesting a contribution of this protein to the development of bronchoconstriction.