Expression of tPA, PDGF-CC and PDGF-alpha (IMAGE) Michigan Medicine - University of Michigan Caption These images show the expression of tpA, PDGF-CC and the PDGF-alpha receptor in the brains of mice. Taken together, they demonstrate that these molecules are concentrated near blood vessels (arterioles) in the brain, interacting with one another on the surface of brain cells adjacent to those vessels. Credit University of Michigan Usage Restrictions None 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.