September 11, 2013
Pepper Spice May Offer Treatment For People With Chronic Pain
Lee Rannals for redOrbit.com - Your Universe Online
Scientists looking into why Szechuan pepper causes a tingling sensation have discovered the Asian spice may help patients with chronic pain.
The new research, published in the journal Proceedings of the Royal Society B, could lead to a greater understanding of the causes of tingling sensations experienced by many chronic pain patients.
Szechuan pepper mimics the sense of touch in the brain by chemically activating light-touch fibers on the lips and tongue. It is a common spice used in Asian cuisine, and some say the pepper can feel like a mild electrical current, such as touching the terminals of a nine-volt battery to the tongue. Dr Nobuhiro Hagura, of the University of College London Institute of Cognitive Neuroscience, said this is the first time they have been able to show how chemicals activate touch fibers, including a measurable frequency.
"We know that natural products like chilli, mustard oil and menthol can activate the thermal and pain fibres in the skin, but we wanted to find out why Szechuan pepper specifically works on the light-touch fibres, producing a conscious sensation of touch and that distinctive tingling feeling," Hagura said in a statement.
When researchers applied Szechuan pepper to the lips of volunteers, the participants were asked to match the frequency of the resulting tingling sensation by adjusting a vibrating stimulus on their fingertips. The team was able to show that an active ingredient in the peppers stimulates specific RA1 fibers in the lips and tongue. These fibers are responsible for transmitting touch sensation, and send the equivalent of a light tap on the skin to the brain at the rate of 50 times per second.
"What we found was that a unique active ingredient in the pepper, called sanshool, activates these fibres, sending a highly specific signal to the brain. Szechuan peppers and physical touch sensations share this same pathway to the brain," Hagura said. "We hope that laboratory studies of the tingling sensations caused by sanshool could help to clarify the brain processes underlying these sensations, and how they are related to pain in some cases."
The researchers said they will be investigating the reasons why people enjoy eating Szechuan pepper, and how touch sensation can help to boost the flavor of food.