Side Effect Discovered with New Painkillers

Ivanhoe Newswire

(Ivanhoe Newswire) -- A dark side has been discovered with a new class of painkillers. A new study finds painkillers that block a receptor called TRPV1 may interfere with brain functions, such as learning and memory.

TRPV1 is a pain receptor whose activation causes the pain in inflammation. Drug companies have been testing TRPV1 receptor blockers as a way to treat the pain of inflammation and nerve damage in peripheral nervous system. Researchers knew that TRPV1 dealt with the nervous system, but were not sure of its function in the brain.

In experiments with rats, researchers from the University of Providence looked to see if TRPV1 plays a role in long-term depression (LTD). LTD is a weakening of the signaling between neurons that takes place at the connections called synapses. LTD is believed to be central in establishing memory pathways in the brain. Study authors say they found they could block LTD in the brain using drugs that block TRPV1.

Study authors say these findings may also explain the role of TRPV1 in the reported side effects of the anti-obesity drug, Acomplia. Acomplia is approved in Europe but was denied FDA approval because of concerns that the drug increased a patients risk of depression and suicide.

In an accompanying editorial, investigators say while there is an uncertain future of TRPV1-targeted drugs, these types of studies are important for drug development and to help researchers have a better knowledge of synaptic function.

Sign up for a free weekly e-mail on Medical Breakthroughs called First to Know by clicking here.

SOURCE: Neuron, 2008;57:746-759

Last updated 3/17/2008.

This article can be accessed directly at:
http://www.healthscout.com/news/1/8018358/main.html