Effect of succinylcholine on the neuromuscular junction of hypoglycemic rats

The aim of the present study was to investigate the effect of neuromuscular blocking drugs on the neuromuscular junction in hypoglycemic rats. Three groups of 6 white adult Wistar albino rats were used. Group A consisted of the control animals with normal blood glucose levels ranging between 80-120 mg/dl. Groups B and C consisted of animals which were made hypoglycemic by intravenous injection of insulin at a dose of 1 iU/100 g b.w. In this way, their blood glucose levels were reduced to 50% of the blood glucose levels of the control animals. The test animals (groups B and C) were sacrificed 40 min after the injection of insulin and the preparations of the phrenic nerve-hemidiaphragm were placed into a 100 ml_bath containing Paradelis-Zaimis solution. The bath was aerized with O2/CO2:95/5%, it's temperature was maintained at 37 degrees C and it's pH at 7.2. After the stabilization of the system and the recording of neuromuscular activity, succinylcholine was administered (1.5 x 10(-8) M in groups A and B and 3.0 x 10(-8) M in group C). For the statistical analysis of the results, student's t-test was used. According to our results, there is a statistically significant difference (with p < 0.02 being considered significant) between the n.bl/t% (magnitude of final neuromuscular blockage) values of the animals of groups B and C and those of the animals of group A. We also observed a statistically significant difference (with p < 0.001 being considered significant) between the t (time required for complete blockage in groups A and C or time required for stabilization of blockage in group B) values of the animals of groups B and C and those of the animals of group A. On the other hand, there was a statistically significant difference (p < 0.02 being considered significant) in the n.bl/5'% (magnitude of neuromuscular blockage 5 min after the administration of succinylcholine) values only between the animals of group A and B. Our results indicate that under hypoglycemic conditions, the amount of succinylcholine required for final neuromuscular blockage is two times greater than that needed under normal glucose blood levels. This finding suggests that the integrity of the neuromuscular junction is altered during hypoglycemia.