痛抑郁二联征模型大鼠中缝背核不同水平5羟色胺表达差异

目的 探讨痛抑郁二联征模型大鼠中缝背核（DRN）5羟色胺（5-HT）阳性细胞的分布特点。 方法 20只雄性SD大鼠随机分为对照组和模型组。模型组大鼠连续3d皮下注射利血平，每日1次，以诱发痛抑郁二联征模型。模型制作后第1天和第2天检测左后足机械缩足阈观察大鼠痛阈变化，模型制作后第2天旷场实验和高架O迷宫实验检测大鼠情绪变化，免疫荧光技术观察DRN前囟后6.8mm、7.3mm和7.8mm水平的5-HT表达。 结果 模型组大鼠经利血平注射后机械痛阈显著下降，并产生抑郁样行为。对照组的DRN前囟后6.8mm、7.3mm和7.8mm水平的5-HT阳性细胞表达量分别为106.00±10.21、96.67±24.50和195.67±2.33。模型组相应的表达量分别为61.67±14.53，72.33±34.35和53.67±26.77。除前囟后7.8mm水平模型组与对照组相比有显著性差异（P<0.05）之外，其他两个水平5-HT阳性细胞表达量模型组和对照组之间差异无显著性（P>0.05）。 结论 利血平诱导的痛抑郁二联征大鼠模型以及中缝背核5-HT表达的降低，可能主要与DRN前囟后7.8mm水平的5-HT阳性细胞数变化有关，而与前囟后6.8mm和后7.3mm 水平无关。

Comparisons of 5-hydroxytryptamine expression at different levels of dorsal raphe nucleus in rats with pain-depression dyad

Objective To observe the distribution of 5-hydroxytryptamine (5-HT) in the dorsal raphe nucleus (DRN) of the rat with pain-depression dyad. Methods Twenty male SD rats were randomly divided into normal group and model group (n=10). The model group had pain-depression dyad induced by subcutaneously injecting reserpine daily for three consecutive days. The behavior was tested by mechanical pain thresholds and the depressive emotion was examined by open-field test and elevated-zero-maze test. The expressions of 5-HT in DRN (bregma-6.8,-7.3,-7.8mm) were detected with immunofluorescence test. Results Compared with the normal group, rats in the model group showed a declined pain threshold of the left hind leg and depressive-like behavior. The 5-HT labeled cells at different levels of DRN (bregma-6.8,-7.3,-7.8mm) of normal rats were 106.00±10.21, 96.67±24.50 and 195.67±2.33, while the model group rats were 61.67±14.53, 72.33±34.35 and 53.67±26.77. In comparison with the normal group, the expressions of 5-HT in DRN (bregma-7.8mm) decreased significantly in the model group (P<0.05), but no changes were observed at the levels of bregma-6.8 and-7.3mm (P>0.05). Conclusions The pain-depression dyad induced by reserpine injection can cause the declination of 5-HT expressions in DRN. The declination may be related with the expressions of 5-HT in DRN (bregma-7.8mm), but not with the levels of bregma-6.8 and-7.3mm.