In in a follow-up experiment using 100 mg/kg Mn/2 day we have replicated the body weight reduction seen here (unpublished observations), indicating that the present body weight changes are not a false positive result. We found a modest increase in prenatal mortality associated with MnOE at the 100 mg/kg/2 day dose reared

under standard housing conditions (10.1%) but not at 50 mg/kg/2 day. In barren cages, both SB203580 ic50 doses increased mortality (9.6% and 12.9% in the 50 and 100 mg/kg/2 day doses, respectively). The latter is presumably the result of an interaction of Mn and stress on survival. Of all the studies reviewed above, most make no statement of morality, i.e., they fail to state that there was or was not any change. There is one report of increased mortality in rats associated with P21-81 Mn exposure [54], and one report of increased resorptions from prenatal Mn exposure [49]. Interestingly, there is one human epidemiological SCH 900776 datasheet study showing a significant association between infant mortality and Mn ground water concentrations across the state of North Carolina [63]. It is difficult to interpret the present mortality data in light of the silence of other reports on this point. Neither

Mn nor barren cage rearing altered baseline corticosterone at the ages tested, but immediately after the acute SWS stressor exposure, standard housed Mn groups showed an exaggerated increase in corticosterone on P19. This response was absent in Mn exposed groups raised in barren housing, suggesting that chronic stress attenuates the normal acute stress response

at this age. In terms of rearing condition alone, housing produced only a trend main effect (F(1,1004) = 2.87, p ≤ 0.09) but it modified the corticosterone response to acute stress. This influence appeared on P19 also in which Barren housed rats showed increased corticosterone after acute stress compared with Standard housed controls. This change was different when Mn effects were overlaid on this pattern. Barren housing suppressed the corticosterone increase caused by Mn Amobarbital at P19. At P29, where no Mn effects on corticosterone were observed, there was a large effect of housing in which Barren housed animals showed a larger response to acute stress at time-0 as reflected in a 3-way interaction of housing x age x time (F(6,1004) = 4.16, p < 0.001). Housing had no main effects on neostriatal, hippocampal, or hypothalamic monoamines or their principal metabolites, although it was an interacting factor with Mn at some ages. These interactions with Mn were complex as they were age-specific and in some cases both age and sex-specific. However, some common threads may be discerned.