Dynamic and Integrated Synaptic Processing ... 131immunoreactivity following mating occurred in cells co-expressing ER-a or
both ER-a/ER-ß in the dorsal MePD (Gréco et al., 2003). This same Fos
detection occurred in cells only co-expressing ER-ß in the ventral MePD
(Gréco et al., 2003). Progesterone receptors also showed complex dynamics in
the female MePD along the estrous cycle or after castration (Gréco et al.,
2001; Isgor et al., 2002). In addition, some MePD cells co-express ER-ß and
progesterone receptors (Gréco et al., 2001)”.
These data indicate the complexity of actions that sex steroids can have in
the MePD of females along normal ovarian cycles or during the
reorganizational period of the brain following OVX. Indeed, there is a variable
hormonal modulation of the postsynaptic dendritic spines or the direct axonal
contacts on dendritic shafts in the neurons of the female MePD (Rasia-Filho et
al., 2004, 2012a; Brusco et al., 2014). In conjunction, the interface between
gonadal steroid actions and neuronal function in the MePD is important for the
interpretation of the social relevance of both olfactory and vomeronasal stimuli
(Pro-Sistiaga et al., 2007; Westberry and Meredith, 2016) and motivation to
socially investigate a conspecific (Dumais et al., 2016), for the response to
genitosensorial stimulation and the modulation of sexually receptive behavior
(Coolen et al., 1997; Pfaus and Heeb, 1997; Newman, 1999), for avoidance of
the offspring or the maternal display (Fleming et al., 1980; Sheehan et al.,
2001), for anxiety and conditioned or innate fear (Adamec and Morgan, 1994;
Ducan et al., 1996) and the emotional processing involved in neuroendocrine
responses to stressful stimuli (Dayas et al., 1999; Singewald et al., 2008; Lin et
al., 2011). In this regard, although glutamate microinjection in the MePD
induced only a subtle increase in carbohydrate food consumption in starved
rats (Rosa et al., 2011), the local administration of corticotrophin releasing
hormone indicates that the MePD affects stress-induced food intake (Hu et al.,
2016). Therefore, the finding that various social behaviors can be modulated
by the MePD suggests “that local cells integrate different demands from
specific pathways. Each pathway provides inputs that are then temporally and
spatially integrated within neural networks to trigger the most appropriate
action according to the animal’s context...” (Rasia-Filho et al., 2012b).
The rat MePD regulates the timing of puberty independently of changes in
body weight and caloric intake, with local glutamatergic systems advancing
the timing of puberty and GABAergic activation delaying it (Li et al., 2015).
At adulthood, estrogen action in the MePD of estrous female rats plays a
critical role for the arousal of interest, sniffing, and expression of preference
for male odors (Fujiwara et al., 2016). The MePD modulates the timely
display of proceptive and lordosis behavior in females at the same time that it