Electromagnetic Field Devices and Their Effects on Nociception and Peripheral Inflammatory Pain Mechanisms.

Context • During cell-communication processes, endogenous and exogenous signaling affects normal and pathological developmental conditions. Exogenous influences, such as extra-low-frequency (ELF) electromagnetic fields (EMFs) have been shown to affect pain and inflammation by modulating G-protein coupling receptors (GPCRs), downregulating cyclooxygenase-2 (Cox-2) activity, and downregulating inflammatory modulators, such as tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) as well as the transcription factor nuclear factor kappa B (NF-κB). EMF devices could help clinicians who seek an alternative or complementary treatment for relief of patients chronic pain and disability. Objective • The research team intended to review the literature on the effects of EMFs on inflammatory pain mechanisms. Design • We used a literature search of articles published in PubMed using the following key words: low-frequency electromagnetic field therapy, inflammatory pain markers, cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), opioid receptors, G-protein coupling receptors, and enzymes. Setting • The study took place at the Wake Forest School of Medicine in Winston-Salem, NC, USA. Results • The mechanistic pathway most often considered for the biological effects of EMF is the plasma membrane, across which the EMF signal induces a voltage change. Oscillating EMF exerts forces on free ions that are present on both sides of the plasma membrane and that move across the cell surface through transmembrane proteins. The ions create a forced intracellular vibration that is responsible for phenomena such as the influx of extracellular calcium (Ca2+) and the binding affinity of calmodulin (CaM), which is the primary transduction pathway to the secondary messengers, cAMP and cGMP, which have been found to influence inflammatory pain. Conclusions • An emerging body of evidence indicates the existence of a frequency-dependent interaction between the mechanical interventions of EMF and cell signaling along the peripheral inflammatory pain pathway.