Endothelin-1, endothelin receptors and ecNOS gene transcription in vital organs during traumatic shock in rats

Endothelin-1 (ET-1) is a vasoconstrictor peptide that may play an important role in the pathophysiology of severe trauma. We examined ET-1 gene expression in vital organs (i.e., heart, lungs, kidneys, liver and small intestine) during murine traumatic shock using ribonuclease protection assays. Our data show that ET-1 mRNA was significantly increased in the lungs two hours after trauma when compared with control anesthetized rats. There was also a significant increase in ET-1 transcripts occurring in the kidneys, heart and liver. During these experimental conditions, we also observed statistically significant increased endothelin type B (ET(B)) receptor mRNA expression in the lung, heart, liver, kidney and small intestine. Expression of endothelial constitutive nitric oxide synthase (ecNOS) gene, which is functionally coupled to ET(B) receptor, also was increased in vital organs during traumatic shock. Endothelin type A (ET(A)) receptor gene expression was slightly decreased in the lung, liver and small intestine. These results suggest that ET-1 and ET(B) mRNA expression are mainly increased in the lung and other vital organs and may play a functional role in the pathophysiology of murine traumatic shock.