[Numerical variation in synaptic ribbons of rat pinealocytes under magnetic storm conditions and on calm days].

Based on the hypothesis of the magnetoreceptor function of the pineal gland, a comparative study has been made, with electronic microscopy, of the numerical variations of the synaptic ribbons of the pinealocytes (indicating the cellular metabolic activity) of the groups of rats, under magnetic storm conditions and in calm days. In this quantitative study it was established that the incidence of synaptic ribbons per each 20,000 microns 2 of pineal tissue was smaller in the group of animals sacrificed during geomagnetic storms, as compared with the other group of animals sacrificed in calm periods (P less than 0.001). It was suggested that the synaptic ribbons may be morphological indicators of the pineal activity, with respect to the variations of the geomagnetic field.