Dose Related Neuromuscular Blocking Effects of d-Tubocursrine Chloride in Rabbits / 대한마취과학회지

ABSTRACT

Patients vary markedly in their responses to d-tubocurarine chloride. Despite an attempt to diminish the variation in responses to relaxants by standardizing experimental techniques, anesthetic concentration kept constant, acid-base status kept constant, premedication omitted, dosage calculated in terms of mg/sq meter body surface, the marked variation was found to persist. The dose related neuromuscular blocking effect of d-tubocurarine chloride was investigated using a rabbit common peroneal nerve anterior tibial muscle preparation. All experimental rabbits tracheas were intubated through tracheostomy under general anesthesia with Nembutal 40 mg/kg intravenously. Reapiration was controlled by a Harvard animal respirator. The body temperature was kept at 35-37 degrees C by a thermoblanket. The degree of neuromuscular block following intravenous d-tubocurarine chloride was measured by single twitch response. The common peroneal nerve was stimulated supramaximally using a square waves of 0. 2 msec duration at a frequency of 0.1 Hz, and each stimulus was repeated once every 10 seconds. The ratio of the twitch height was calculated. The results were as follows 1) No neuromuscular blocking effect was observed with 0.1 mg/kg of intravenous d-tubocu- rarine chloride. 2) 100% of neuromuscular blocking effect was observed with more than 1mg/kg of intravenous d-tubocurarine chloride. This is 5 to 10 times higher than the human dose. 3) Dose related prolonged neuromuscular blocking effect was observed from d-tubocurarine chloride in rabbits.