Nerve Cells Responding to Pain (image) Johns Hopkins Medicine Caption Nerves in mouse skin that are actively responding to the painful stimulus capsaicin have been genetically engineered to glow green. Hairs appear in yellow. Credit David Rini Usage Restrictions None 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.