Effect of midazolam pretreatanent on neurotoxicity of ropivacaine in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the preventive effect of midazolam pretreatment against neurotoxicity of ropivacaine and the underlying mechanism. Methods Thirty male SD rats aged 4-6 months weighing 250-300 g were randomly divided into 3 groups with 10 animals in each group group Ⅰ blank control; group Ⅱ ropivacaine (R) and group Ⅲ midazolam-ropivacaine (M-R). In group R and M-R 0.75% ropivacaine was infused i.v. at a rate of 0.5 ml?min-1 until the animal developed convulsion. The animals were killed and brains were immediately removed for detennination of glutamate, aspartate, glycine and GABA content in the brain. Venous blood samples were taken for determination of pH and plasma concentration of lactate. The total amount of ropivacaine infused was calculated.Results The plasma lactate concentration was significantly higher and pH was significantly lower in group R than in blank control group. The concentrations of the 4 amino acids in the brain were significantly increased in group R and M-R as compared with the blank control group. The aspartate, glycine and GABA contents in the brain were significantly lower in M-R group than in R group. The total amount of ropivacaine infused i.v. was significant larger in group M-R than in group R.Conclusion Midazolam pretreatment can prevent the neurotoxicity of ropivacaine by modulating the balance between excitatory and inhibitory amino acids.