Antinociceptive Effects in Normal and Diabetic Rats Exposed to 50 Hz Magnetic Field

Abstract

The effects of repeated applications of alternating sinusoidal 50 Hz magnetic field, MF (B = 5.0 mT, 165-min-long sessions everyday, each including four 30-min-long exposures separated by 15-min-long intervals, carried out for 30 days), on thermonociception (estimated using the tail-flick test) were examined in intact rats, diabetic rats (induction by streptozotocin), and diabetic rats treated with insulin. Exposures to MF led to mild (several percent) increases in the tail-flick latency, TFL, immediately after each session and a sustained rather significant rise in this parameter (increment up to 40%) developing with some delay, from 2 to 4 days. The latter effect was limited in time (lasting 2 days long); then, the TFLs tended to rapidly return to initial (or nearly initial) values. This intense hypoalgesic effect induced by MF exposures was observed on days 3 and 4 in normal rats, on days 4 and 5 in diabetic rats, and on days 5 and 6 in diabetic rats treated with insulin. Significant increases in the mean arterial blood pressure were observed in diabetic rats; exposures to MF exerted no significant influence on this parameter in both normal and diabetic animals. Mechanisms of the development of diabetic neuropathy and those of the hypoalgesic actions of MF are discussed. The MF-induced antinociception seems to be, in future, an attractive choice for the relief of acute and chronic symptoms in diabetic neuropathy, but further detailed studies are necessary to find optimum MF parameters, modes of application, and "time windows."