Effects of pancuronium and vecuronium on creatine phosphokinase in rat isolated heart, liver, kidney and diaphragm.

1. The effects of two muscle relaxants, namely, pancuronium and vecuronium, on creatine phosphokinase (CPK) release from four different types of tissues, namely, heart, liver, kidney and diaphragm, were studied in the rat in vitro. 2. The total, neat and CPK levels (units/ml), released by muscle relaxants were measured using spectrophotometric determination at 340 nm. 3. The results showed that both muscle relaxants, in low concentrations, i.e. 0.34 or 0.32 microM, close to a clinical dose of 0.1 mg/kg, had no significant effect on CPK leakage in all four types of tissues studied. However, in concentrations 12-122 times clinical dose, the two muscle relaxants produced differential adverse effects in the tissues studied. 4. In most concentrations, pancuronium and vecuronium produced significant increases in the CPK release in the kidney and diaphragm. In contrast, pancuronium had no significant effect on CPK release in the liver and the lowest effect in the heart. Similar results were obtained with vecuronium. 5. The clinical relevance and/or implications of the present results are discussed and the results are compared to those previously reported by other workers in other preparations.