text: Unlike the sedative hypnotics that target GABA(A) receptor complexes, << ramelteon >> is a chronohypnotic that acts on the melatonin MT(1) and [[ MT(2) ]] receptors, which are primarily located in the suprachiasmatic nucleus, the body's "master clock." As such, ramelteon possesses the first new therapeutic mechanism of action for a prescription insomnia medication in over three decades.