Search for Magnetite Nanoparticles in the Rats’ Brain

Various animals (bacteria, bees, fishes, birds, etc.) show the ability to find orientation in the geomagnetic field. This magnetoreception effect can be explained by the presence of small biogenic magnetite crystals in their organisms that interact with the geomagnetic field. Some studies carried out on rodents show that they respond to magnetic stimulation in the earth's magnetic field by the expression of activity genes like C-fos, but the mechanism of magnetoreception for them it is still unknown. In this paper, the amount of magnetite of two brains and two cerebellums of Sprague-Dawley rats was measured using ferromagnetic resonance spectroscopy. No presence of magnetite (with a limit of a few picograms) was found. This means that either biogenic magnetite is not located in the brain, but somewhere else, or that the magnetic field sensibility in rats is not related to biogenic magnetite.