ABSTRACT
Remifentanil is widely used to control intraoperative pain. However, its analgesic effect is limited by the generation of postoperative hyperalgesia. In this study, we investigated whether the impairment of transmembrane protein 16C (TMEM16C)/Slack is required for α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptor (AMPAR) activation in remifentanil-induced postoperative hyperalgesia. Remifentanil anesthesia reduced the paw withdrawal threshold from 2 h to 48 h postoperatively, with a decrease in the expression of TMEM16C and Slack in the dorsal root ganglia (DRG) and spinal cord. Knockdown of TMEM16C in the DRG reduced the expression of Slack and elevated the basal peripheral sensitivity and AMPAR expression and function. Overexpression of TMEM16C in the DRG impaired remifentanil-induced ERK1/2 phosphorylation and behavioral hyperalgesia. AMPAR-mediated current and neuronal excitability were downregulated by TMEM16C overexpression in the spinal cord. Taken together, these findings suggest that TMEM16C/Slack regulation of excitatory synaptic plasticity via GluA1-containing AMPARs is critical in the pathogenesis of remifentanil-induced postoperative hyperalgesia in rats.
ABSTRACT
@#Objective To explore the physiological characteristics of synaptic transmission of anterior horn early development in thorac-ic spinal cord mediated byα-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in rats. Methods 36 Wistar rats were divided into embryonic 17 days group (E17, n=12), embryonic 20 days group (E20, n=12) and postnatal 7 days group (P7, n=12). Immuno-fluorescent staining of calmodulin-dependent protein kinaseⅡ(CaMKⅡ) was used to test the distribution of AMPA receptors. Multi-elec-trode array technique (MED-64 system) was used to test the changes of field excitatory post-synaptic potential (fEPSP) of synaptic transmis-sion mediated by AMPA receptor. Results There was small amount of CaMKⅡ-positive neurons existing in gray matter of spinal cord at E17, CaMKⅡ-positive neurons migrated to the center, and the number of neurons became more and more in E20 and P7 rats. The number of evoked fEPSP gradually increased in rats from E17 to P7, and could be blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). The range of synaptic connection in spinal cord gray matter significantly reduced (P<0.001). Conclusion AMPA receptors participate in the early development of spinal cord in rats and act as the main excitatory receptor of functional synaptic connection in neural network of ventricornu.