Here’s what you’ll learn in this story:Pain happens when specialized nerve cells that detect painful stimuli communicate with the brain. One of these ways involves using an inhibitory protein that responds to light pulses and shuts off nerve signals. The drug allows for pain signals to be switched on and off at will. And 8.5 percent of them had pain that “frequently limited life or work activities.”Pain is one of many electrical signals neurons transmit. This condition causes chronic bladder pain and overactive bladder.