Abstract: Objective To investigate the gender difference of GABAAα3 receptor expression in the ventrolateral periaqueductal gray (vLPAG) of rats with neuropathic pain. Methods Twenty-four SD rats were divided into 2 groups: 12 females in group F and 12 males in group M. Neuropathic pain model was established by spared nerve injury (SNI) of sciatic nerve branches. The mechanical pain threshold and cold pain threshold were recorded at each time point (1 day before operation and 1, 3, 7, 14 days after operation). Western blotting was used to detect the expression level of GABAAα3 receptor at vLPAG. Results The mechanical and cold allodynia were significantly higher in both group F and group M after operation. The mechanical pain threshold of group F was lower than that of group M (P<0.05), and the frequency of cold foot contraction in group F was higher than that in group M (P<0.05). 14 days after the model establishment, the expression level of GABAAα3 receptor protein increased significantly at vLPAG, and it was higher in group F than that in group M (P<0.05). Conclusions Female rats are more sensitive to neuropathic pain than male rats and the up-regulation of GABAAα3 receptor expression at vLPAG may be related to the decrease of pain threshold in rats.

Key words: neuropathic pain, gender, ventrolateral periaqueductal gray, vLPAG , GABAAα3