Weak magnetic fields antagonize the effects of melatonin on blood glucose levels in Parkinson's disease.

Abstract

Treatment with picoTesla magnetic fields recently has been reported to attenuate symptoms of Parkinson's disease (PD). The mechanisms by which weak magnetic fields ameliorate Parkinsonian symptoms are unknown. There is evidence that the pineal gland is a "magnetosensor" in the brain since in experimental animals exposure to external magnetic fields alters the firing rate of pineal cells and induces inhibition of melatonin secretion. Hence, the clinical effects of weak magnetic fields in PD likewise may involve the mediation of the pineal gland. Animal data indicate that the pineal gland is involved in the regulation of glucose metabolism and that exogenous administration of melatonin induces an hyperglycemic effect. To investigate the hypothesis that the pineal gland mediates the therapeutic properties of weak magnetic fields in PD, I studied the effects of orally administered melatonin (3.0 mg) followed by a 6 minute application of low intensity external weak magnetic fields (7.5 picoTesla) on blood glucose levels in two Parkinsonian patients. In both patients melatonin challenge produced a moderate hyperglycemic effect which was reversed by subsequent stimulation with weak magnetic fields. These findings support the hypothesis that weak magnetic fields inhibit melatonin secretion and that the antiParkinsonian properties of weak magnetic fields are mediated partially via the inhibition of melatonin secretion. Furthermore, these data suggest that melatonin receptor antagonists could be beneficial as an adjunctive treatment in PD and highlight the importance of the pineal-hypothalamic axis in the pathophysiology of the disease as well as in the mechanisms of action of antiParkinsonian drugs.