Effects Of Adrenomedullin On The Cultured Astrocytes

Experimental background and significance:Adrenomedullin(Adrenomedullin,AM)is a fifty-two amino acid neuropeptide,it is one of the members of the calcitonin gene related peptide(calcitonin-gene related,peptide,CGRP)family.The main physiological function is to diastolic blood vessels and reduce blood pressure.In recent years it has been confirmed that it can participate in the occurrence of pain.According to previous research results of others and our laboratory's past research work,we hypothesized that AM could activate astrocytes.In order to prove the correctness of this hypothesis,we first established a method for the cultivation and purification of astrocytes with high purity.On this basis,we further explore investigate the effect of AM on astrocytes in normal and inflammatory pathological conditions.Methods:Primary cultured rat astrocytes.AM and LPS were used to induce the activation of the astrocytes.Then antagonist AM_22-52was used to confirm the role of AM receptors in the astrocytes by AM and LPS.We used western blot,immunocytochemistry and real-time quantitative PCR techniques to examine the changes in cellular morphology and function of the astrocytes.Results:First,a large number of high purity astrocytes were cultured.(1)AM activates astrocytes and increases the protein expression of GFAP and p ERK in astrocytes.AM_22-52 can inhibit the up-regulation of the protein expression of GFAP and p ERK in astrocytes caused by AM(2)Astrocytes were activated by LPS(1 g/ml)for six hours,Astrocytes get larger and rounder,Fluorescence intensity of glial fibrillary acidic protein increased and the expression of GFAP,IL-1 and TNF-m RNA in astrocytes increased significantly.AM_22-52can inhibit the up-regulated m RNA expression of GFAP,IL-1?and TNF-?in astrocytes caused by LPS.Conclusion:The above results indicate that AM can directly activate astrocytes mediated via the AM receptors,causing the changes of act factors in cells,thus participating in the occurrence of inflammatory pain.