QX-314 (chloride) is primarily used in neuroscience research as a sodium channel blocker. It is applied to selectively inhibit neuronal activity in specific cells or regions, often in conjunction with optogenetics or electrophysiology techniques. This allows researchers to study the role of sodium channels in neuronal signaling and pain pathways. Additionally, it has been explored for its potential in pain management, as it can block pain signals without affecting motor function when administered locally. Its use is limited to experimental settings due to its specificity and mechanism of action.