Razi Journal of Medical Sciences

    The increasing presence of low intensity uniform magnetic fields in different environments such as factories, industries, hospitals, in transport and electrical devices and medical application has become so important. Therefore, conducting an investigation on the effects of magnetic fields on properties and revenues of human body’s different tissues, especially nerve tissue, seems necessary from protection and medical application viewpoint. In this respect, the present study was undertaken to investigate the effect of low intensity uniform magnetic fields on nerve signals’ electrical conduction velocity. In this study, 0.5mT magnetic field was exposed on neuromuscular junction of abductor polices brevies muscle and median peripheral motor nerve. The latency and nerve electrical conduction velocity in left wrist of 30 healthy men, before and after exposure to the magnetic field was measured by stimulating and recording device (Cadwell 5200 A). The results indicated that magnetic field causes decrease in nerve signals electrical conduction velocity due to increase of neuromuscular neurotransmitters revenues, latency or increase of muscular fibers signal transmission latency (P<0.05). Increase in latency and decrease of electrical conduction velocity in neuromuscular junction may be due to the Lorants force effect of magnetic field on neuro transmitters (such as acetylcholine) or increasing neuromuscular space distance. Also, the increase of muscle fibers signals transmission latency may be due to Ca²⁺ concentration or fibers excitability level changes.