Pineal 'synaptic ribbons' and serum melatonin levels in the rat following the pulse action of 52-Gs (50-Hz) magnetic fields: an evolutive analysis over 21 days.

In continuation of earlier studies, we have investigated the influence of 52-Gs (50-Hz) magnetic fields on the evolution of pinealocyte 'synaptic ribbons' and serum melatonin levels in rats, following 30 min daily exposure. The animals were sacrificed after 1, 3, 7, 15 and 21 days. A significant decrease in the number of synaptic ribbons was observed after 15 and 21 days, together with a significant drop in serum melatonin concentrations after 15 days. The mediating role of the retina in these modifications and magnetic field effects is discussed.