[Effect of laudanosine on catecholamine release in dogs]

It is well established that a large dose of atracurium (more than twice ED95) produces significant release of histamine in the blood accompanying hypotension but recovery to control level within a few minutes after the administration of atracurium. We speculated that laudanosine, a metabolite of atracurium may play an important role in preventing this cardiovascular disaster due to histamine release. From this concept, we investigated the effect of laudanosine on the release of epinephrine and norepinephrine in dogs, anesthetized with halothane, nitrous oxide and oxygen. Two different doses of laudanosine (1 microgram.kg-1 and 10 micrograms.kg-1) were selected and serum catecholamine levels were measured with HPLC in six dogs. Intravenous injection of 1.0 microgram.kg-1 laudanosine increased NE level from 0.11 +/- 0.03ng.ml-1 to 0.13 +/- 0.04ng.ml-1 at 3 minutes after the injection. Blood pressure, heart rate, pulmonary arterial pressure, pulmonary wedge pressure and central venous pressure did not change significantly. The intravenous injection of 10 micrograms.kg-1 laudanosine increased NE level from 0.09 +/- 0.02ng.ml-1 to 0.14 +/- 0.02ng.ml-1 at 1 minutes after the injection, but there was no remarkable cardiovascular effect. From this study we conclude that the intravenous injection of laudanosine increased serum NE level, but there was no significant hemodynamic change in the dogs.