Capsaicin is the substance in hot peppers that makes them hot, and it may also inhibit certain channels in neurons involved in pain processing.
Although a complete understanding of how capsaicin works remains unclear, researchers have gained new insight into the underlying mechanisms that may be involved in pain reduction.
Tibor Rohacs, MD, an associate professor of pharmacology and physiology at Rutgers New Jersey Medical School in Newark, New Jersey, recently reported data that shows capsaicin appears to activate the transient receptor potential vanilloid (TRPV1) ion channel, which is normally activated by heat.
“Capsaicin induces pain acutely. If you ever tasted chili peppers, you must know the feeling. After a while, however, capsaicin desensitizes the TRPV1 receptor and some other ion channels in the sensory neurons. This may lead to pain relief. On an even longer time-scale, it may also induce degeneration of the pain-sensing nerves. That may also be part of its pain-reducing action,” said Rohacs.
Understanding the Mechanisms of Capsaicin Action
Currently, there are two potential ways researchers are trying to utilize the capsaicin receptor for pain relief: Applying capsaicin or finding another activator of TRPV1 locally to desensitize the nerves.
Research efforts by Rohacs and colleagues have found that in addition to desensitizing the TRPV1 pain receptor, capsaicin also silences the ion channels that are activated by mechanical stimuli. These were recently shown to be very important for touch sensation. These mechano-sensitive ion channels are called Piezo 1 and 2. This may be part of the mechanism in how capsaicin inhibits mechanical pain.1