Greg Miller in ScienceNOW Daily News:
Capsaicin, the compound that puts the fire in jalapeños and habañeros, has already been marketed as a balm for stiff joints and arthritis. But a new study harnesses capsaicin’s special affinity for pain-sensing neurons in a more clever way, using it to open tiny channels on the cells’ surfaces so that another drug–an anesthetic–can get inside. The work could lead to treatments that dull pain without causing numbness or temporary paralysis.
Many local anesthetics work by blocking sodium channels, pores on the surface of neurons that let ions flow into the cells to generate the electrical impulses neurons use to communicate. Blocking sodium channels blocks more than just pain, however. It also shuts down nerves carrying touch information, as well as those that control movement. That’s why people sometimes leave the dentist’s office drooling, slurring their speech, and unable to feel their tongues.