Chili Pepper Too Can Now Rescue From Pain

A dentist's injection typically causes numbness for several hours. This experience could soon be history. Scientists have been able to block the pain and numb feeling that lingers long in the gums after a visit to the dentist using chili peppers.

Local anesthetics are pain killers which are used during operations whereby patients remain alert during the procedure and thus, do not require general anesthesiadefine. These common analgesics, including lidocaine, affect all neurons in the treated area. As a result, along with the pain receptors, the touch receptors are also blocked producing numbness. Neurons, controlling muscles, are silenced as well, producing a temporary paralysis.

Clifford Woolf, a professor at Harvard Medical School and the Massachusetts General Hospital, Boston, USA and his colleagues have developed a combination of two agents which is able to specifically block pain without producing numbness or motor paralysis.

In order to do this the scientists used a normally inactive, positively charged form of the local anesthetic lidocaine called QX314. This particular type of lidocaine is not able to pass through the cell membrane of neurons because it is charged. Since, local anesthetics only operate inside neurons, an injection of QX314 alone is ineffective, unlike lidocaine which passes easily through the membrane of all cells and therefore, blocks all neurons.

As QX314 only enters pain neurons and thereby, acts exclusively as a pain killer, the researchers combined it with capsaicin, the pain-producing substance in chili peppers. Capsaicin binds a membrane receptor which is only present in the membrane of neurons responsible for pain perception. Thus, the chili pepper substance opens channels, enabling QX314 to get into the cell and then block the pain receptors.

Using rats, the scientists could show that, when applied to the animal’s hind paws, the combination of QX314 and capsaicin exclusively blocks pain receptors. While completely blocking the response to painful stimuli, the animals could, nevertheless, move normally and were responsive to touch.

There is, however, one disadvantage of this current strategy. Capsaicin activates the sensors for pain and heat. This is the reason why people burn their mouth when they eat chili. To use the pain killing combination in patients, another way of opening the channel must be found to allow the QX314 into the cell without capsaicin causing its typical, painful, heat sensation until, the QX314 gets into the cell and then kills the pain.

However, attempts are being made to solve this problem and recent findings promise new non-painful ways of targeting QX314 into pain fibers. Once perfected, this will be the first example of using the body’s own cellular channels as a drug delivery system, targeting treatment only at pain fibers. A sure relief for all dental patients and mother’s to be, during labor.