Morphodynamic reactive response of the pineal gland of rats chronically exposed to stable strong magnetic field.

Mature male Wistar rats were affected by a strong magnetic field of 0.70 T for 20 min per day for 2 weeks. A short distance between the electromagnet pole expansions allowed interposition of one restrained animal only. The results obtained showed that the immobilization stress increased the peptidergic activity of both light and dark pinealocytes. In the animals exposed to the magnetic field, a dual morphodynamic response was observed: the peptidergic activity of light pinealocytes was obviously reduced versus the unimpaired stress-stimulated functional engagement of dark pinealocytes. The probability that the retina----pineal gland magnetoreceptor-magnetoeffector circuit is formed through the accentuation of the suppression of the noradrenaline input on light pinealocytes is discussed. It is also hypothesized that a potentially harmful bioeffect of a strong magnetic field could be manifested second to the impairment of the activity of light pinealocytes in organisms coping with stress.