Medial preoptic area and onset of maternal behavior in the rat

Three experiments examined whether the medial preoptic area (MPOA) is involved in the onset of maternal behavior in the rat. Exp I, with 54 female Charles River CD rats, investigated whether estradiol benzoate (EB) acts on the MPOA to facilitate the onset of maternal behavior in 16-day pregnant, hysterectomized, and ovariectomized Ss. When given EB implants in the MPOA, these Ss had significantly shorter latencies for the onset of maternal behavior than those implanted with cholesterol in the MPOA or with EB in the ventromedial hypothalamus, in mammillary bodies, or under the skin. Exp II, with 62 Ss, showed that estrogen-induced prolactin release was not involved in this facilitation. Exp III, with 35 Ss, showed that MPOA lesions disrupted the onset of maternal behavior induced by pup stimulation in virgin females. (11/2 p ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).