Objective        To explore the effect of dexamethasone (Dex) on intracellular calcium concentration ([Ca

2+

]

i

) in cultured astrocytes of rat spinal dorsal horn and the relative mechanism.       Methods        Astrocytes obtained from neonatal SD rat spinal cord were cultured and purified. Changes of [Ca

2+

]

i

in cultured dorsal spinal cord astrocytes were detected with confocal laser scanning microscopy using fluo-4/AM as a calcium fluore

scent indicator.       Results        Dex induced a rapid elevation of [Ca

2+

]

i

in the cultured astrocytes within several minutes in a dose-dependent manner (P0.05)

and the elevation could be blocked by pertussis toxin (PTX

a blocker of G protein activation

100 ng/mL) rather than by glucocorticoid receptor antagonist RU38486 (10 μmol/L). In addition

cycloheximide (CHX

protein-synthesis inhibitor

10 μg/mL) pretreatment could not impair the Dex-induced [Ca

2+

]

i

elevation.        Conclusion        These observations suggest that a non-genomic pathway may be involved in the effect of Dex on [Ca

2+

]

i

elevation in cultured astrocytes of spinal dorsal horn

and the effect may be mediated by G-protein-coupled membrane-bound glucocorticoid receptor (mGCR).