Both postnatal handling, which increases maternal LG (see above), and rearing by a high-LG mothers enhance serotonin (5-hydroxytryptamine [5-HT]) turnover in the hippocampus in day-6 rat pups.73,74 Interestingly, postnatal handling results in specific increases in 5-HT in the hippocampus and prefrontal cortex, where GR expression is increased.74 5-HT levels in the hypothalamus, septum, and amygdala are unaffected; GR levels in these regions are not altered by handling. Thus, the sensory input associated with maternal LG selectively alters 5-HT activity in specific brain regions.
