脂多糖对大鼠下丘脑室旁核GABA_BR1阳性神经元的激活作用

Activation of GABA_BR1 neurons in hypothalamic paraventricular nucleus of rat by lipopolysaccharide

目的:探讨大鼠下丘脑室旁核(PVN)-氨基丁酸B受体亚单位1(GABABR1)阳性神经元对脂多糖(LPS)刺激的反应.方法:将大鼠腹腔注射LPS建立免疫应激模型,对照组注射等量的生理盐水,采用免疫荧光双标记与激光共聚焦显微镜技术,观察大鼠下丘脑室旁核内神经元Fos和GABABR1的标记情况以及它们在同一神经元内是否有共标记.结果:腹腔注射LPS可使大鼠PVN内表达Fos神经元数量显著增高,且PVN内部分神经元可同时被Fos和GABABR1双重标记,双重标记的神经元大约占Fos神经元的30%,占GAB-ABR1的24%.结论:下丘脑室旁核部分GABABR1阳性神经元参与了LPS诱导的免疫应激反应,它们可能在下丘脑-垂体-肾上腺轴的调节方面起重要作用.

AIM： To investigate whether the neurons containing γ-aminobutyric acid B receptor 1 subunit（ GABABR1 ） in the hypothalamic paraventricular nucleus（PVN） are involved in the immuno-stimulating stress induced by lipopolysaccharide （LPS） in the rats. METHODS： LPS was intraperitoneally injected into rats to stimulate the immune system and same volume of normal saline was give in control group as well. Immunofluorescence double staining and laser scanning confocal microscopy was used to observe the expression of Fos and GABABR1 as well as the relationship between the two in the PVN. RESULTS： A large number of Fos and GABABR1 positive neurons were observed in the PVN. The number of Fos positive neurons was increased significantly after the LPS immuno-stimulating in contrast to control group. Fos/GABABR1 double-labeled neurons were mainly observed in the area of medial parvocellular subdivision close to lateral magnocellular subdivision. The proportion of Fos/GABABR1 double-labeled neurons to Fos or GABABR1 single positive neurons was 30% and 24% respectively. CONCLUSION ： Some of GABABR1 positive neurons in the PVN participate in immunostimulating stress and they may play important role in regulation of hypothalamic-pituitary-adrenocortical or stress axis.