Nerve Cells Light Up As They Respond To Pain (video) Johns Hopkins Medicine Share Print E-Mail Loading video... Caption Nerve cells in the skin of a mouse ear light up when activated. Application of capsaicin activates only pain-sensing nerve cells, in a dose-dependent fashion, while potassium chloride (KCl) activates all nerve cells present. The video shows more nerves lighting up each time during the sequential application of a low dose of capsaicin, a higher dose of capsaicin (6 sec), and then KCl (10 sec). Credit Yushim Kim and Xinzhong Dong, courtesy of Neuron Usage Restrictions None Share Print E-Mail 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.