Prenatal restraint stress decreases neurogranin expression in rat offspring hippocampus / 生理学报

Neurogranin, a neuron-specific postsynaptic protein, has been considered to play an important role in synaptic plasticity and learning and memory. The present study aimed to investigate the effects of prenatal restraint stress on neurogranin expression in rat offspring hippocampus. Pregnant rats were given a restraint stress (3 times a day for 7 d, 45 min each time) at the late stage of gestation except that in the control group. The offspring rats were divided into four groups: female control group, male control group, female stress group and male stress group. Expression of neurogranin was determined by immunohistochemistry and Western blot. The results showed that neurogranin-positive immunostaining was detected in all areas of the hippocampus. The staining density was stronger in the CA1 and CA3 regions than that in the dentate gyrus (DG) region. Western blot assay showed that neurogranin protein level in female and male prenatal stressed offspring was significantly lower than that in the controls (P<0.01). Neurogranin level was significantly lower in the female stress group than that in the male stress group, whereas there was no significant gender difference in the control group. Immunohistochemical data further confirmed these results. The present study provides evidence that prenatal restraint stress induces gender-dependent decrease in neurogranin expression in the offspring hippocampus. The prenatal restraint stress-induced decrease in neurogranin expression in the hippocampus might be associated with the deficit in spatial learning and memory reported previously.

Effects of prenatal stress on kinetic properties of high-voltage-activated Ca2+ channel in freshly isolated offspring rat hippocampal CA3 pyramidal neurons / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of prenatal stress (PNS) on kinetic properties of high-voltage-activated (HVA) Ca(2+) channel in freshly isolated offspring rat hippocampal CA3 pyramidal neurons.</p><p><b>METHODS</b>The pregnant rats were exposed to restraint stress, and the hippocampal CA3 pyramidal neurons were freshly isolated from the offspring rats to record voltage-gate Ca(2+) channel currents in these neurons using whole-cell configuration of patch-clamp technique.</p><p><b>RESULTS</b>PNS significantly increased HVA calcium current density and integral current but did not alter the steady-state activation and steady-state inactivation properties of HVA Ca(2+) channel in the offspring rat CA3 neurons. The maximal HVA calcium current density was -40.89-/+0.31 pA/pF in the control group (n=10) and -49.44-/+0.37 pA/pF in PNS group (n=8, P<0.01). The maximal integral current of the HVA Ca(2+) channel was 106.81-/+4.20 nA*ms in the control group (n=10) and 133.49-/+2.59 nA*ms in the PNS group (n=8, P<0.01).</p><p><b>CONCLUSION</b>Maternal exposure to stress during the critical phase of pregnancy may result in long-lasting effects on the ion channels of the hippocampal neurons in the offspring rats.</p>

Gender-dependent difference of NF-kappaB expression in the hippocampus of prenatally stressed offspring rats / 生理学报

In this study, immunohistochemistry and Western blot were used to determine whether the expression of NF-kappaB in the hippocampus of prenatally stressed offspring rats is gender-dependent. The results were as follows: In the female offspring rats, the expressions of p65 in the hippocampal dentate gyrus in mid-term stress (MS) and late-term stress (LS) groups were significantly less than that in the control group (P<0.01). There was a significant difference between MS and LS groups (P<0.01). The expressions of p50 in all regions of hippocampus in MS and LS groups were significantly more than that in the control group (P<0.01). A significant difference was also present between MS and LS groups (P<0.01). In the male offspring rats, the expressions of p65 in the hippocampal dentate gyrus in MS and LS groups were evidently more than that in the control group (P<0.01). There was a significant difference between MS and LS groups (P<0.01). The expressions of p50 in all regions of hippocampus in MS and LS groups were significantly less than that in the control group (P<0.05, P<0.01). There was also a significant difference in p65 expression between MS and LS groups (P<0.01). In addition, in the control group the expressions of p65 in the hippocampal dentate gyrus of female offspring rats were significantly more than that of male ones (P<0.01). However, in LS group the expressions of p65 in the hippocampal dentate gyrus of female offspring rats were significantly less than that of male ones (P<0.01). Moreover, there was no significant difference in p65 expression between female and male offspring rats in MS group. In the control group the gender difference in the expression of p50 was only observed in hippocampal CA1 (P<0.01). The expressions of p50 in all regions of hippocampus of female offspring rats were significantly more than that of male ones in LS group (P<0.01). There was no significant difference in p50 expression between female and male offspring rats in MS group. The results of Western blot were similar to those of immunohistochemical study. These results indicate that prenatal stress in different gestational periods significantly affects the expressions of p65 and p50 in hippocampus, and this effect is gender-dependent. This may be one of the mechanisms underlying the gender difference in the ability of learning and memory of the prenatally stressed offspring rats.