Featured Research

from universities, journals, and other organizations

Hot Chili Peppers Help Unravel The Mechanism Of Pain

Date:
February 24, 2009
Source:
Public Library of Science
Summary:
Capsaicin, the active ingredient in spicy hot chili peppers such as the jalapeno, is most often experienced as an irritant, but it may also be used to reduce pain. New research uses capsaicin to uncover novel insight into how pain-receptor systems can adapt to painful stimuli.

Researchers have used capsaicin -- the chemical that makes peppers like this jalapeno spicy hot -- to uncover novel insight into how pain-receptor systems can adapt to painful stimuli.
Credit: iStockphoto/Chris Bence

Capsaicin, the active ingredient in spicy hot chili peppers such as the jalapeno, is most often experienced as an irritant, but it may also be used to reduce pain. A new work published by Drs. Feng Qin and Jing Yao in this week's PLoS Biology uses capsaicin to uncover novel insight into how pain-receptor systems can adapt to painful stimuli.

Related Articles


Sensory systems are well known to adapt to prevailing stimuli. For example, adaptation happens when your eyes adjust from a dark movie theater during a matinee to the bright sunlight outside. Whether pain receptors truly adapt or rescale their responses (versus simply desensitizing) has been an open question.

Capsaicin acts by binding to a receptor in the cell wall of nerve endings and triggering an influx of calcium ions into the neuron. Eventually, the nervous system interprets this cascade of events as pain or heat, depending on which nerves are stimulated. Scientists had previously linked the pain-relieving effects of capsaicin to a lipid called PIP2, found in cell membranes. When capsaicin is applied to the skin it induces a strong depletion of PIP2 in the cell membrane.

"The receptor acts like a gate to the neurons," said Qin. "When stimulated it opens, letting outside calcium enter the cells until the receptor shuts down, a process called desensitization. The analgesic action of capsaicin is believed to involve this desensitization process. However, how the entry of calcium leads to the loss of sensitivity of the neurons was not clear."

Capsaicin creams are commonly sold over the counter as effective treatment for a variety of pain syndromes, from minor muscle or joint aches to those that are very difficult to treat, such as arthritis and neuropathic pain.

By combining electrical and optical measurements, the authors now have been able to link directly the depletion of PIP2 and the desensitization of the receptor. The authors also showed that the receptor is fully functional after desensitization – i.e. although you stop feeling pain – are desensitized – if another event occurs that would normally trigger a 'pain' response – such as an increased concentration of capsaicin - the desensitization does not affect that feeling.

"What changed was the responsiveness threshold," said Qin. "In other words, the receptor had not desensitized per se, but its responsiveness range was shifted. This property, called adaptation, would allow the receptor to continuously respond to varying stimuli over a large capsaicin concentration range."

The findings have implications for pain sensation mechanisms as well as clinical applications. With an adaptive response, the receptors are essentially autoregulated without a fixed threshold, thus the intensity of the pain you experience is dependent on the recent history of pain.


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. Yao J, Qin F. Interaction with phosphoinositides confers adaptation onto the TRPV1pain receptor. PLoS Biol, 2009; 7(2): e1000046 DOI: 10.1371/journal.pbio.1000046

Cite This Page:

Public Library of Science. "Hot Chili Peppers Help Unravel The Mechanism Of Pain." ScienceDaily. ScienceDaily, 24 February 2009. <www.sciencedaily.com/releases/2009/02/090223221232.htm>.
Public Library of Science. (2009, February 24). Hot Chili Peppers Help Unravel The Mechanism Of Pain. ScienceDaily. Retrieved November 20, 2014 from www.sciencedaily.com/releases/2009/02/090223221232.htm
Public Library of Science. "Hot Chili Peppers Help Unravel The Mechanism Of Pain." ScienceDaily. www.sciencedaily.com/releases/2009/02/090223221232.htm (accessed November 20, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Says It Will Scale Up Its Ebola Response

UN Says It Will Scale Up Its Ebola Response

AFP (Nov. 20, 2014) UN Resident Coordinator David McLachlan-Karr and WHO representative in the country Daniel Kertesz updated the media on the UN Ebola response on Wednesday. Duration: 00:51 Video provided by AFP
Powered by NewsLook.com
Takata Offers "sincerest Condolences" To Victims of Malfunctioning Airbag

Takata Offers "sincerest Condolences" To Victims of Malfunctioning Airbag

Reuters - US Online Video (Nov. 20, 2014) U.S. Congress hears from a victim and company officials as it holds a hearing on the safety of Takata airbags after reports of injuries. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Obesity Costs Almost As Much As War And Terrorism

Obesity Costs Almost As Much As War And Terrorism

Newsy (Nov. 20, 2014) The newest estimate of the cost of obesity is pretty jarring — $2 trillion. But how did researchers get to that number? Video provided by Newsy
Powered by NewsLook.com
Ebola Crisis Affecting US Adoptions

Ebola Crisis Affecting US Adoptions

AP (Nov. 20, 2014) The Sanborn family had hoped they'd be able to bring home their 5-year-old adopted son from Liberia by now. But Ebola has forced them to wait. The boy is just one of thousands of orphans in West Africa who've been impacted by the deadly virus. (Nov. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins