Proposed Cellular Mechanism (IMAGE) Hiroshima University Caption This image shows the treatment of primary cultured astrocytes with amitriptyline activates matrix metalloproteinases (MMPs) and receptor tyrosine kinases (RTKs, i.e., fibroblast growth factor receptor [FGFR] and epidermal growth factor receptor [EGFR]). Activated RTKs increase the mRNA and protein expression of EGR1, which in turn increases FGF2 mRNA expression. Credit Hiroshima University Usage Restrictions This image may only be used with appropriate caption and credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.