Emerging research suggests electrical stimulation of certain regions in the brain releases an opiate-like substance that can reduce severe pain.
Experts say the substance released is considered one of the body’s most powerful painkillers.
In a new study, researchers stimulated the brain of an individual with chronic, severe facial pain to release an opiate-like substance.
The findings expand on previous studies where researchers delivered electricity through sensors on the skulls of chronic migraine patients, and found a decrease in the intensity and pain of their headache attacks.
However, the researchers then couldn’t completely explain how or why.
The current findings help explain what happens in the brain that decreases pain during the brief sessions of electricity, says Alexandre DaSilva, D.D.S., D.Med.Sc., an assistant professor of biologic and materials sciences at the University of Michigan School of Dentistry.
In their current study, DaSilva and colleagues intravenously administered a radiotracer that reached important brain areas in a patient with trigeminal neuropathic pain (TNP), a type of chronic, severe facial pain.
They applied the electrodes and electrically stimulated the skull right above the motor cortex of the patient for 20 minutes during a PET scan (positron emission tomography). The stimulation is called transcranial direct current stimulation (tDCS).
The radiotracer was specifically designed to measure, indirectly, the local brain release of mu-opioid, a natural substance that alters pain perception.
Researchers say that pain relief occurs when an opiate binds with a receptor called the mu-opioid receptor (the study assessed levels of this receptor).
“This is arguably the main resource in the brain to reduce pain,” DaSilva said. “We’re stimulating the release of our (body’s) own resources to provide analgesia. Instead of giving more pharmaceutical opiates, we are directly targeting and activating the same areas in the brain on which they work.
“(Therefore), we can increase the power of this pain-killing effect and even decrease the use of opiates in general, and consequently avoid their side effects, including addiction.”
Most pharmaceutical opiates, especially morphine, target the mu-opioid receptors in the brain, DaSilva says.
A low dose of electricity is used to stimulate the brain (2mA) – significantly less than the 200 to 1600 milliamperes (mA) dosage of electroconvulsive therapy used to treat depression and other psychiatric conditions.
Researchers found that just one session immediately improved the patient’s threshold for cold pain by 36 percent, but not the patient’s clinical, TNP/facial pain.
This suggests that repetitive electrical stimulation over several sessions are required to have a lasting effect on clinical pain as shown in their previous migraine study, DaSilva says.
Research findings are discussed in the journal Frontiers in Psychiatry.
Investigators also say that the next step will investigate long-term effects of electric stimulation on the brain and find specific targets in the brain that may be more effective depending on the pain condition and patients’ status. For example, the frontal areas may be more helpful for chronic pain patients with depression symptoms.
Source: University of Michigan