Alexandra DaSilva and colleagues from the University of Michigan, Harvard University and the City University of New York stimulated the brain's endogenous supply of morphine to target areas in patients suffering from chronic, severe facial pain using sensitive electrodes in a study published on 2 November 2012. This is excellent news, because the possible practice of using electricity to stimulate our own endogenous painkilling opioid drugs logically reduces our dependency on external sources of the same drug.
Writes the University of Michigan's Laura Bailey, "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 [morphine], a natural substance that alters pain perception. In order for [an] opiate to function, it needs to bind to the mu-opioid receptor [of which the study assessed the levels.]
"The dose of electricity is very small, he says. Consider that electroconvulsive therapy (ECT), which is used to treat depression and other psychiatric conditions, uses amperage in the brain ranging from 200 to 1600 milliamperes (mA). The tDCS protocol used in DaSilva's study delivered 2 mA, considerably lower than ECT.
"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, DaSilva says."
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