Heat and pain

Hot.

ScienceDaily (Jul. 5, 2006)

The old wives’ tale that heat relieves abdominal pain, such as colic or menstrual pain, has been scientifically proven by a UCL (University College London) scientist, who will present the findings today at the Physiological Society’s annual conference hosted by UCL.
Dr Brian King, of the UCL Department of Physiology, led the research that found the molecular basis for the long-standing theory that heat,such as that from a hot-water bottle applied to the skin, provides relief from internal pains, such as stomach aches, for up to an hour.

Dr King said: “The pain of colic, cystitis and period pain is caused by a temporary reduction in blood flow to or over-distension of hollow organs such as the bowel or uterus, causing local tissue damage and activating pain receptors.

“The heat doesn’t just provide comfort and have a placebo effect – it actually deactivates the pain at a molecular level in much the same way as pharmaceutical painkillers work. We have discovered how this molecular process works.”

If heat over 40 degrees Celsius is applied to the skin near to where internal pain is felt, it switches on heat receptors located at the site of injury. These heat receptors in turn block the effect of chemical messengers that cause pain to be detected by the body.

The team found that the heat receptor, known as TRPV1, can block P2X3 pain receptors. These pain receptors are activated by ATP, the body’s source of energy, when it is released from damaged and dying cells. By blocking the pain receptors, TRPV1 is able to stop the pain being sensed by the body.

(2006, July 5). Heat Halts Pain Inside The Body. ScienceDaily. Retrieved March 19, 2008, from http://www.sciencedaily.com­ /releases/2006/07/060705090603.htm