The maternal behavior (CM) is important for all mammals, including humans (MATTSON et al., 2001; Numan & Stolzenberg, 2009). The dramatic transition in maternal response that occurs between mating and lactation is one of the most striking behavioral changes that occur in adult animals (Lonstein et al., 2003). The emergence and maintenance of CM are controlled by the interaction of environmental factors, biochemical, hormonal and neural (NUMAN, 2006).The medial preoptic area (MPOA) is a critical neural site for the hormonal action during delivery that triggers the onset of maternal behavior, since the MPOA neurons express receptors for estrogen, progesterone, prolactin and oxytocin, which are key to this answer (Simerly et al. 1990; Kremarik et al. 1995; Numan, et al. 1999; Bakowska and Morrell, 2003). Furthermore, the expression of maternal behavior leads to an increase in the MPOA of Fos observed especially when females are in contact with pups, since the removal thereof induces a decrease in expression of Fos in the MPOA. Therefore, the MPOA may be modulated both by hormonal information about the sensory information, both critical to the emergence and maintenance of maternal responses. Additionally the MPOA plays a key role in the expression of maternal behavior and may act both in appetitive phase (grouping of pups and nest building) and phase consummatory behavior (breastfeeding).In recent work, PEREIRA and MORRELL, 2009, showed that inactivation of the MPOA at the end of lactation, maternal behavior and restores retards the end of lactation, indicating that the neural activation of this website would be important to signal the end of lactation.Of particular interest for studies KNOLLEMA et al. (1992) and RONDINIi et al. (2010) demonstrated an increased expression of MCH mRNA in the MPOA at 190 days of lactation period ending care Since the end of lactation coincides with the increase in the expression of melanin-concentrating hormone (MCH) on the ventral the MPOA (vMPOA) and that activation of this sector would be critical to the completion of maternal care related to the development of offspring, we can infer that the increased expression of MCH could this be related to inhibition of maternal behavior.In order to validate the hypothesis that increased expression of melanin-concentrating hormone (MCH) in the ventral portion of the medial preoptic area (vMPOA) and activation of this sector are directly related and that this link would be of paramount importance to the end of maternal care, would be relevant investigate the pattern of efferent projection of this particular sector of the medial preoptic area, determining how the vMPOA could modulate its efferent targets, signaling the end of lactation.
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