Treating Chronic Pain At The Source
Dr. Mark Shapiro, professor of physiology at the Health Science Center is working to create a novel, safe and effective way to control pain at its source. Dr. Shapiro is senior author of the research, which is reported in the journal, Neuron.
If translated into a therapy, this approach would be completely different from current pain-control methods, which frequently lead to addiction and overdoses, Shapiro said. Pain therapy could even be tailored to each patient using the strategy.
How would the new approach work? Charged salt atoms (called ions) such as calcium and sodium pass in and out of cells through protein pores called ion channels.
The Health Science Center researchers discovered that two ion channels in sensory nerve cells are interacting in unexpected ways. Sensory nerve cells are neurons that initiate the sensations of pain, or burning heat or cold.
“One ion channel we studied, called TRPV1, starts the signal that tells the brain something hurts,” Dr. Shapiro said. “The other channel, a calcium ion channel called CaV1.2, signals genes to turn on or off in response to activity, such as painful stimuli. We observed that proteins of these ion channels interact with each other and function in tandem, which isn’t supposed to happen because it was thought that those two processes occurred in different parts of the neuron.”
Ion channels are in the outer membranes of all cells including neurons, the cells of the nervous system. The finding that these two ion channels are coupled has important implications for all neurons. This includes both sympathetic neurons, which control autonomic functions of the body such as heart rate and breathing, and sensory neurons, which sense painful stimuli and sound the alarm to the brain.
The ramifications for pain control are especially exciting to Dr. Shapiro and his colleagues.
“The most unexpected, exciting and provocative result of this work,” he said, “is the discovery that the ion channel that starts the pain signal is intimately associated with the ion channel that turns on or off genes’ response. They are locked together. It’s as if two people are in locked arms, and when one takes a step, the other moves in lockstep.”
This article was originally published in The University of Texas Health Science Center at San Antonio’s Newsroom.