Patrizio M, Costa T, Levi G
Neurobiology Section, Istituto Superiore di Sanita, Rome, Italy.
Glia. 1995 Jun;14(2):94-100. doi: 10.1002/glia.440140204.
The aim of the present study was to determine whether two classical macrophage activators, bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) could affect the accumulation of the second messenger cAMP in cultured rat microglia and astrocytes. Purified microglia and astrocyte secondary cultures obtained from the neonatal rat were grown for 3 days in basal medium Eagle (BME) + 10% fetal calf serum (FCS). Exposure of microglia to LPS resulted into a dose- and time-dependent decrease in the accumulation of cAMP induced by receptor-mediated (isoproterenol or prostaglandin E2) or direct (forskolin) activation of adenylate cyclase. The inhibitory effect of LPS was rapid (a 10 min preincubation was sufficient to approach a maximal effect), occurred at low doses (IC50 = 1.2 ng/ml), and was not abrogated by pertussis toxin. A selective inhibitor of type IV phosphodiesterase (rolipram, 100 nM) prevented the effect of LPS on cAMP accumulation, while inhibitors of other forms of phosphodiesterase were unable to do so. IFN-gamma (100 u/ml) also caused a depression of the evoked cAMP accumulation in microglia after a 10 min preincubation, and its effect was prevented by rolipram, as in the case of LPS. Astrocytes differed from microglia in that LPS (1-100 ng/ml) did not inhibit the accumulation of cAMP induced by either isoproterenol or forskolin; on the other hand, IFN-gamma did have an inhibitory effect (though less pronounced than in microglia) that could be prevented by rolipram.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是确定两种经典的巨噬细胞激活剂，即细菌脂多糖（LPS）和干扰素-γ（IFN-γ）是否会影响培养的大鼠小胶质细胞和星形胶质细胞中第二信使环磷酸腺苷（cAMP）的积累。从新生大鼠获得的纯化小胶质细胞和星形胶质细胞原代培养物在伊格尔基础培养基（BME）+10%胎牛血清（FCS）中培养3天。小胶质细胞暴露于LPS会导致由受体介导（异丙肾上腺素或前列腺素E2）或直接（福斯高林）激活腺苷酸环化酶诱导的cAMP积累呈剂量和时间依赖性下降。LPS的抑制作用迅速（预孵育10分钟足以达到最大效应），在低剂量时出现（IC50 = 1.2 ng/ml），且不受百日咳毒素的消除。IV型磷酸二酯酶的选择性抑制剂（咯利普兰，100 nM）可阻止LPS对cAMP积累的影响，而其他形式磷酸二酯酶的抑制剂则无法做到。IFN-γ（100 u/ml）在预孵育10分钟后也会导致小胶质细胞中诱发的cAMP积累减少，其作用与LPS一样可被咯利普兰阻止。星形胶质细胞与小胶质细胞不同，LPS（1 - 100 ng/ml）不会抑制异丙肾上腺素或福斯高林诱导的cAMP积累；另一方面，IFN-γ确实有抑制作用（尽管不如在小胶质细胞中明显），且可被咯利普兰阻止。（摘要截断于250字）
