Analysis of adaptation mechanisms during environmental stress through the neural-immune interaction.

(1)冷暴露(4℃，1hr)时，大鼠视前内侧区、下丘脑外侧区和下丘脑腹内侧区c-fos基因表达增加；热暴露(33℃，1hr)时，视前内侧区、下丘脑腹内侧区和下丘脑室旁核CRF基因表达增加；(2)大鼠腹腔注射Poly I：C(mg/kg)后，自发跑轮活动受到抑制，持续1周以上。在此期间，皮质和下丘脑的干扰素-α和5-羟色胺转运体(5-HTT)基因表达增加。(3)热暴露可引起老龄大鼠大脑皮质IL-1β、COX-2和核因子抑制物(NF-κB-β)mRNAs及内毒素含量增加。由于内毒素抑制剂预处理减轻了这些β和内毒素水平的升高，推测热暴露引起的细菌易位是脑内IL-1 mRNA及其相关物质mRNAs表达增加的机制之一。(4)在体脑微透析显示注射PolyI：C后前额叶皮质细胞外5-羟色胺浓度下降。此外，5-HT1A受体激动剂8-羟基-2-(二正丙氨基)四氢丙氨酸(8-OH-DPAT)可减弱聚I：C对转轮活动的抑制作用。(5)在小鼠海马片苔藓纤维-CA3通路中应用造血细胞因子干细胞因子(SCF)调节双脉冲易化作用，提示SCF在海马区突触可塑性中起一定作用。

(1) Amount of c-fos mRNA increased in the medial preoptic area (MPO), lateral hypothalamic area (LHA), and ventromedial hypothalamus (VMH) during cold exposure (4 ℃, 1 hr), while CRF mRNA increased in the MPO and paraventricular hypothalamus (PVN) during heat exposure (33 ℃, 1 hr) and in the MPO and LHA during cold. (2) Intraperitoneal injection of poly I:C (mg/kg) in rats induced suppression of spontaneous running wheel activity for more than one week. During this period IFN-α and serotonin transporter (5-HTT) mRNA increased in the cortex and hypothalamus. (3) Heat exposure induced increase in IL-1β, COX-2 and inhibitor of nuclear factor (NF)-κB-β mRNAs, as well as lipopolysaccharide (LPS) content in the cortex of aged rats. Since pretreatment with an endotoxin inhibitor attenuated the increases in these mRNAs and LPS levels, it was suggested that bacterial translocation induced by heat exposure was one of the mechanisms of the increased expression of IL-1β and its related substances mRNAs in the brain. (4) In vivo brain microdialysis revealed that the extracellular concentration of 5-HT in the prefrontal cortex decreased after poly I:C injection. In addition, the poly I:C-induced suppression of the running wheel activity was attenuated by 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetraline (8-OH-DPAT). (5) Application of a hematopoietic cytokine, stem cell factor (SCF), modulated paired-pulse facilitation in the mossy fiber-CA3 pathway in the mouse hippocampal slices, suggesting that SCF plays a role in the synaptic plasticity in the hippocampus.