Effects of propofol on phosphorylation of AMPA receptor GluR1 subunits in a rat model of visceral pain / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of propofol on the phosphoryhtion of α-amino-3-hydroxy5-methyl-4-isoxazolepropionate(AMPA)receptor GluR1 subunits at Serine-831 and Serine-845 sites in the spinal cord dorsal horn in a rat model of visceral pain.Methods Thirty male SD rars,aged 6-8 weeks,weighing 200300 g,in which intrathecal catheters were successfully placed without complications,were randomly divided into 3 groups(n-=10 each)sham operation group(group Ⅰ),visceral pain group(group Ⅱ)and propofol group (group Ⅲ).Visceral pain was induced by injection of 10％ capsaicin 50μl via the rectum in groups Ⅱ and Ⅲ.While the equal volume of normal saline was given instead in group Ⅰ.Group Ⅲ received intrathecal injection of propofol 20 tg at 10 min before injection of capsaicin.While the equal volume of dimethyl sulfoxide was given instead of propofol in groups Ⅰ and Ⅱ.The cumulative pain score was recorded during 30 min after capsaicin injection.The rats were then sacrificed,and the lumbar segment(L3-6)of the spinal cord was removed for determination of the expression of GluR1 subunits and phosphorylation of GluR1 subunits at Serine-831 and Serine-845 sites in the spinal cord dorsal horn.Results Compared with group Ⅰ,the cumulative pain score and phosphorylation of GluR1 subunits at Serine-831 sites and Serine-845 in the spinal cord dorsal horn were significantly increased(P ＜0.05 or 0.01),but there were no significant differences in the expression of GluR1 subunits in groups Ⅱ and Ⅲ (P ＞ 0.05).Compared with group Ⅱ,the cumulative pain score and phosphorylation of GluRl subunits at Serine831 and Serine-845 sites in the spinal cord dorsal horn were significantly decreased in group Ⅲ(P ＜ 0.05 or 0.01).Conclusion Propofol can attenuate the visceral pain through the inhibition of the phosphorylation of AMPA receptor GluR1 subunits at Serine-831 and Serine-845 sites in tte rat spinal cord dorsal horn.