Melatonin Synthesis in the Pineal Gland: Effect of Light Mediated by the Sympathetic Nervous System

Abstract
Exposure to light reduces the ability of the rat pineal gland to synthesize melatonin and decreases the weight of the gland. When the sympathetic nerves to the pineal gland are cut, light no longer has an effect on melatonin synthesis or pineal weight. The response of the gland does not require that the gonads or the pituitary gland be present.