Blocking pain receptors extends lifespan

Researchers have said that blocking a pain receptor in mice not only extends their lifespan, but also gives them a more youthful metabolism, including an improved insulin response that allows them to deal better with high blood sugar.

Andrew Dillin, a professor of molecular and cell biology at the University of California, Berkeley, and senior author of a new paper describing these results, said they think that blocking this pain receptor and pathway could be very, very useful not only for relieving pain, but for improving lifespan and metabolic health, and in particular for treating diabetes and obesity in humans.

He said that as humans age they report a higher incidence of pain, suggesting that pain might drive the aging process.

The "hot" compound in chili peppers, capsaicin, is already known to activate this pain receptor, called TRPV1 (transient receptor potential cation channel subfamily V member 1).

In fact, TRPV1 is often called the capsaicin receptor. Constant activation of the receptor on a nerve cell results in death of the neuron, mimicking loss of TRPV1, which could explain why diets rich in capsaicin have been linked to a lower incidence of diabetes and metabolic problems in humans.

More relevant therapeutically, however, is an anti-migraine drug already on the market that inhibits a protein called CGRP that is triggered by TRPV1, producing an effect similar to that caused by blocking TRPV1. Dillin showed that giving this drug to older mice restored their metabolic health to that of younger mice.

Dillin and his team found that mice genetically manipulated to lack TRPV1 receptors lived, on average, nearly four months - or about 14 percent - longer than normal mice. The TRPV1-deficient mice also showed signs of a youthful metabolism late in life, due to low levels of CGRP - a molecule that blocks insulin release resulting in increased blood glucose levels and thus could contribute to the development of type 2 diabetes. Throughout aging, these mice showed improved ability to quickly clear sugar from the blood as well as signs that they could burn more calories without increasing exercise levels.

Moreover, old mice treated with the anti-migraine drug, which inhibits the activity of CGRP receptors, showed a more youthful metabolic profile than untreated old mice.

The study has been published in the journal Cell.