Role of nNOS-NOS1AP coupling in remifentanil-induced hyperalgesia in rats / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of neuronal nitric oxide synthase (nNOS)-nitric oxide synthase 1 adaptor protein (NOS1AP) coupling in remifentanil-induced hyperalgesia in rats.Methods:Forty clean-grade healthy adult male Sprague-Dawley rats, weighing 240-260 g, aged 2-3 months, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), remifentanil group (group R), nNOS-NOS1AP inhibitor ZLc002 group (group C+ Z) and remifentanil + ZLc002 group (group R+ Z). Normal saline was intravenously infused at a rate of 0.1 ml·kg -1·min -1 for 60 min in C group. Remifentanil was intravenously infused at a rate of 1.0 μg·kg -1·min -1 for 60 min in R group. ZLc002 10 mg/kg was intraperitoneally injected for 3 consecutive days, and then normal saline 0.1 ml·kg -1·min -1 and remifentanil 1.0 μg·kg -1·min -1 were intravenously infused for 60 min in C+ Z group and R+ Z group. The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 24 h before intravenous infusion and 6, 24 and 48 h after intravenous infusion (T 0-3). All the rats were sacrificed after the last measurement of pain thresholds, and the L 4-6 segments of the spinal cord were removed for determination of the expression of nNOS, NOS1AP and Dexamethasone-induced Ras-related protein 1 (Dexras1) protein and mRNA using the real-time polymerase chain reaction. Nitrosylated proteins were extracted by biotin conversion for determination of the expression of nNOS, NOS1AP and total and nitrosylated Dexras1 (by Western blot) and co-expression of nNOS-NOS1AP (by co-immunoprecipitation). The content of NO in the spinal cord was measured. Results:Compared with group C, the MWT was significantly decreased, and the TWL was shortened at T 1-3, the expression of nNOS and NOS1AP protein and mRNA was up-regulated, the co-expression of nNOS-NOS1AP and NO production were increased, and the expression of nitrosylated Dexras1 was up-regulated in group R ( P<0.05), and no significant change was found in each aforementioned parameter in group C+ Z ( P>0.05). Compared with group R, the MWT was significantly increased, and the TWL was prolonged at T 1-3, the co-expression of nNOS-NOS1AP and NO production were decreased, the expression of nitrosylated Dexras1 was down-regulated ( P<0.05), and no significant change was found in the expression of nNOS and NOS1AP protein and mRNA in group R+ Z ( P>0.05). There were no significant differences in total Dexras1 protein and mRNA expression among the four groups ( P>0.05). Conclusions:The mechanism by which remifentanil induces hyperalgesia may be related to up-regulating the expression of nNOS and NOS1AP in the spinal cord, promoting interaction between nNOS and NOS1AP and mediating NO generation and Dexras1 nitrosylation modification in rats.