P45 and P75 (IMAGE) Salk Institute Caption The presence of p45 (green staining) and p75 (red staining) indicates that motor neurons increase both p45 and p75 expression after sciatic nerve injury in an animal. Credit Salk Institute for Biological Studies 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.