Effects of histamine on mRNA expression of Egr-1 in astrocytes / 中国病理生理杂志

ABSTRACT

AIM:To explore whether histamine can regulate the expression of early growth response factor-1 (Egr-1) in the cerebral cortex astrocytes.METHODS:Normal wild-type (WT) mice, histidine decarboxylase knockout ( HDC-KO) mice and histamine treated HDC-KO mice were sacrificed for extracting the total RNA of the cerebral cortex. Primary cultured rat cortical astrocytes were treated with histamine at concentrations of 10 -8 , 10 -7 , 10 -6 , 10 -5 or 10 -4 mol/L for 15, 30, 60, 120 or 240 min.H1 or H2 receptor antagonists were pretreated for 15 min before histamine treat-ment.After histamine treatment, the cell total RNA or protein was extracted.The expression of Egr-1 at mRNA and protein levels was determined by real-time PCR and Western blot.RESULTS:The mRNA level of Egr-1 in cerebral cortex of HDC-KO mice was significantly lower than that in WT mice, while exogenous histamine induced the mRNA expression of Egr-1 in HDC-KO mice.In cultured astrocytes, histamine induced the mRNA expression of Egr-1.The maximum increase in the mRNA level of Egr-1 was produced by histamine at concentration of 10 -5 mol/L.In addition, histamine-induced Egr-1 mRNA accumulation peaked at 30 min after commencing stimulation, while histamine significantly increased Egr-1 protein expression at 60 min.Furthermore, histamine-induced Egr-1 expression was inhibited by H1 receptor antagonist but not H2 receptor antagonist.CONCLUSION:Histamine up-regulates the Egr-1 expression in cerebral cortex and cultured astrocytes, which may attribute to H1 receptor activation.