title: Rapid elevation of calcium concentration in cultured dorsal spinal cord astrocytes by corticosterone.
abstract: In addition to the classic genomic effects, increasing evidence suggests that GC can generate multiple rapid effects on many tissues and cells through nongenomic pathway. In the present study, the effects of corticosterone (CORT) on the intracellular calcium concentration ([Ca(2+)]i) in cultured dorsal spinal cord astrocytes were detected with confocal laser scanning microscopy using fluo-4/AM as a calcium fluorescent indicator that could monitor real-time alterations of [Ca(2+)]i. CORT (0.01-10 μM) caused a rapid increase in [Ca(2+)]i with a dose-dependent manner in cultured dorsal spinal cord astrocytes. The action of CORT on astrocytic [Ca(2+)]i was blocked by pertussis toxin (a blocker of G protein activation, 100 ng/ml), but was unaffected by RU38486 (glucocorticoid receptor antagonist, 10 μM). In addition, cycloheximide (protein-synthesis inhibitor, 10 μg/ml) pretreatment could not impair the CORT-evoked [Ca(2+)]i elevation. Furthermore, Ca(2+) mobilization induced by CORT was abolished by chelerythrine chloride (protein kinase C inhibitor, 10 μM), but was not impaired by H89 (protein kinase A inhibitor, 10 μM). These observations suggest that a nongenomic pathways might be involved in the effect of CORT on [Ca(2+)]i in cultured dorsal spinal cord astrocytes. In addition, our results also raise a possibility that a putative pertussis toxin-sensitive mGCR (G-protein-coupled membrane-bound glucocorticoid receptor) and the downstream activation of protein kinase C may be responsible for CORT-induced Ca(2+) mobilization in cultured dorsal spinal cord astrocytes.
authors.affiliation: Department of physiology, Zunyi Medical College, 201 Dalian Street, Zunyi, Guizhou 563000, People's Republic of China.
authors.forename: Junwei
authors.initials: J
authors.lastname: Zeng
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Zhi
authors.initials: Z
authors.lastname: Xiao
authors.forename: Yuanshou
authors.initials: Y
authors.lastname: Chen
authors.forename: Quanzhong
authors.initials: Q
authors.lastname: Chang
authors.forename: Hong
authors.initials: H
authors.lastname: Tian
authors.forename: Huan
authors.initials: H
authors.lastname: Jin
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Liu
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003345:Corticosterone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D020671:Posterior Horn Cells / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D002118:Calcium; D003345:Corticosterone