Hansson E, Westerlund A, Björklund U, Olsson T
Department of Clinical Neuroscience and Rehabilitation, The Sahlgrenska Academy, University of Gothenburg, 413 45 Gothenburg, Sweden.
Neuroscience. 2008 Sep 9;155(4):1237-49. doi: 10.1016/j.neuroscience.2008.04.027. Epub 2008 Apr 23.
In order to imitate the in vivo situation with constituents from the blood-brain barrier, astrocytes from newborn rat cerebral cortex were co-cultured with adult rat brain microvascular endothelial cells. These astrocytes exhibited a morphologically differentiated appearance with long processes. 5-HT, synthetic mu-, delta- or kappa-opioid agonists, and the endogenous opioids endomorphin-1, beta-endorphin, and dynorphin induced higher Ca(2+) amplitudes and/or more Ca(2+) transients in these cells than in astrocytes in monoculture, as a sign of more developed signal transduction systems. Furthermore, stimulation of the co-cultured astrocytes with 5-HT generated a pronounced increase in intracellular Ca(2+) release in the presence of the inflammatory or pain mediating activators substance P, calcitonin gene-related peptide (CGRP), lipopolysaccharide (LPS), or leptin. These Ca(2+) responses were restored by opioids so that the delta- and kappa-opioid receptor agonists reduced the number of Ca(2+) transients elicited after incubation in substance P+CGRP or leptin, while the mu- and delta-opioid receptor agonists attenuated the Ca(2+) amplitudes elicited in the presence of LPS or leptin. In LPS treated co-cultured astrocytes the mu-opioid receptor antagonist naloxone attenuated not only the endomorphin-1, but also the 5-HT evoked Ca(2+) transients. These results suggest that opioids, especially mu-opioid agonists, play a role in the control of neuroinflammatory activity in astrocytes and that naloxone, in addition to its interaction with mu-opioid receptors, also may act through some binding site on astrocytes, other than the classical opioid receptor.
为了用来自血脑屏障的成分模拟体内情况，将新生大鼠大脑皮层的星形胶质细胞与成年大鼠脑微血管内皮细胞进行共培养。这些星形胶质细胞呈现出具有长突起的形态学分化外观。与单培养的星形胶质细胞相比，5-羟色胺、合成的μ-、δ-或κ-阿片受体激动剂以及内源性阿片肽内吗啡肽-1、β-内啡肽和强啡肽在这些细胞中诱导出更高的Ca(2+)振幅和/或更多的Ca(2+)瞬变，这是信号转导系统更发达的标志。此外，在炎症或疼痛介导激活剂P物质、降钙素基因相关肽（CGRP）、脂多糖（LPS）或瘦素存在的情况下，用5-羟色胺刺激共培养的星形胶质细胞会导致细胞内Ca(2+)释放显著增加。阿片类药物可恢复这些Ca(2+)反应，因此δ-和κ-阿片受体激动剂减少了在P物质+CGRP或瘦素孵育后引发的Ca(2+)瞬变数量，而μ-和δ-阿片受体激动剂减弱了在LPS或瘦素存在时引发的Ca(2+)振幅。在LPS处理的共培养星形胶质细胞中，μ-阿片受体拮抗剂纳洛酮不仅减弱了内吗啡肽-1，还减弱了5-羟色胺诱发的Ca(2+)瞬变。这些结果表明，阿片类药物，尤其是μ-阿片受体激动剂，在星形胶质细胞的神经炎症活动控制中起作用，并且纳洛酮除了与μ-阿片受体相互作用外，还可能通过星形胶质细胞上除经典阿片受体之外的某些结合位点发挥作用。
