[Changes of energy metabolism in canine respiratory muscles after phrenic nerve transection]

To examine the changes in energy metabolism in the respiratory muscles of canines with unilateral phrenic nerve transection using high-performance liquid chromatography (HPLC).

The left phrenic nerve of 8 canines was transected and the contents of adenine nucleotide in respiratory muscles were determined by HPLC before and 1 and 2 months after the operation.

In the intercostal muscles, ATP contents remained almost unchanged during the entire course of the observation, while ADP content was elevated 2 months after the operation as compared with that measured before and 1 month after the operation (P<0.05). One month postoperatively, the content of total adenylic acid (TAN) decreased to the lowest point, but the difference between the measurements was not statistically significant; also at 1 month after the operation, the content of adenylate energy charge (AEC) was the lowest, with statistically significant difference from the measurements before and 2 months after the operation (P<0.05). In the diaphragm, the contents of ATP, ADP, TAN and AEC 2 months postoperatively were 9.05+/-12.70, 2.99+/-2.57, 14.72+/-13.98, 0.57+/-0.29, significantly different from the levels at the other two time points (P<0.05).

After unilateral phrenic nerve transection in canines, the energy metabolism of the diaphragm declines significantly, whereas that of the intercostal muscle can be compensated to some extent.