Changes in circulating plasma met-enkephalin concentrations in feline intestinal ischemia--reperfusion

Plasma met-enkephalin-like immunoreactivity (MLI) levels were determined in cats before, during and after 90 min of intestinal ischemia followed by reperfusion and compared with the levels in control cats. Blood pressure and heart rate were registered and small intestinal mucosal lesions were graded. In control animals, the circulation was stable and there were no mucosal injuries. In the shock group, blood pressure decreased, heart rate increased and severe mucosal lesions were found. The circulating MLI levels were significantly higher 30 min after reperfusion of the ischemic intestine in the shock group than in the control group. There were correlations between MLI and tachycardia and hypotension respectively. Met-enkephalin was released in shock animals after reperfusion of the ischemic intestine and may explain naloxone responsiveness in intestinal shock models.