Role of NL-1 in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horn during remifentanil-induced hyperalgesia in mice with incisional pain / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of neuroligin 1 (NL-1) in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horns during remifentanil-induced hyperalgesia in mice with incisional pain.Methods Forty SPF healthy male C57BL/6J mice,aged 8-10 weeks,weighing 18-22 g,were divided into 5 groups (n=8 each) using a random number table method:control group (group C),NL1-shRNA plasmid group (group NL),incisional pain plus remifentanil group (group I+R),incisional pain plus remifentanil plus blank vector group (group I+R+B),and incisional pain plus remifentanil plus NL-1-shRNA plasmid group (group I+R+NL).Negative lentivirus was intrathecally injected in group I+R+B.In NL and I+R+NL groups,10 μl NL-1-shRNA lentivirus at 1×10s IFU/ml was intrathecally injected once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected at the same time point in C and I+R groups.After transfection was stable,normal saline 0.1 ml was injected via the caudal vein for 4 consecutive times at 15 min intervals in C and NL groups.In I+R,I+R+B and I+R+NL groups,0.1 ml remifentanil 10 μg/kg was injected via the caudal vein for 4 consecutive times at 15 min intervals,and the model of incisional pain was established after the first administration.The mechanical paw withdrawal threshold (MWT) and tail-flick latency (TFL) were measured at 24 h before normal saline or remifentanil administration (T0) and at 3,6,24 and 48 h after the end of administration (T1-4).The animals were sacrificed after measurement of pain threshold at T4,and L4-6 segments of the spinal dorsal horn were then collected for determination of the expression of NL-1 protein and mRNA and AMPA receptors,and the ratio of AMPA receptor expression in the membrane protein to that in the total protein (m/t ratio) was calculated.Results Compared with group C,the MWT was significantly decreased,and TFL was shortened at T1-4,the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was up-regulated,and m/t ratio was increased in I+R and I+R+B groups (P＜0.05).Compared with I+R and I+R+B groups,the MWT was significantly increased and TFL was prolonged at T1-4,the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was down-regulated,and m/t ratio was decreased in group I+R+NL (P＜0.05).Conclusion NL-1 in spinal cord dorsal horns can promote the trafficking of GluR1-containing AMPA receptors to cell membrane,which is involved in the development and maintenance of remifentanil-induced hyperalgesia in mice with incisional pain.