Brain research. Developmental brain research
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Brain Res. Dev. Brain Res. · Sep 2005
Fetal origin of adverse pregnancy outcome: the water disinfectant by-product chloroacetonitrile induces oxidative stress and apoptosis in mouse fetal brain.
Epidemiological studies indicate a relationship between water disinfectant by-products (DBP) and adverse pregnancy outcomes (APO) including neural tube defects. These studies suggest that fetal brain may be vulnerable to DBP during early stages of development. Therefore, we examined several molecular markers commonly known to indicate chemical-induced neurotoxicity during fetal brain development following prenatal exposure to the DBP; chloroacetonitrile (CAN). ⋯ Caspase-3 activity in cerebral cortex and cerebellum of treated animals were also increased (1.7- and 1.5-fold, respectively). In conclusion, this study indicates that CAN/M crossed the placenta and accumulated in fetal brain tissues where it caused oxidative stress and neuronal apoptosis. These events could predispose the fetus to altered brain development leading to APO as well as behavioral and learning and memory deficits.
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Brain Res. Dev. Brain Res. · Aug 2005
Comparative StudyEffects of opioid receptor and alpha2-adrenoceptor agonists on slow ventral root potentials and on capsaicin and formalin tests in neonatal rats.
The inhibitory effects of morphine and alpha2-adrenoceptor agonists on slow ventral root potentials (slow VRP) following ipsilateral dorsal root stimulation in neonatal rat spinal cord were compared with the analgesic effects of these drugs on formalin and capsaicin tests in neonatal rats. Morphine, (D-Phe2, D-Pen5)-enkephalin (DPDPE), dexmedetomidine, clonidine and xylazine showed concentration-related inhibition of slow VRP. The order of potency was dexmedetomidine>morphine=DPDPE>clonidine>xylazine. ⋯ The inhibitory potency for slow VRP by these drugs seems to be correlated with that for capsaicin-induced body movement but not that for formalin-induced one. Dexmedetomidine and morphine in combination inhibited slow VRP and body movement induced by capsaicin in an additive manner. It is suggested that the antinociceptive effects of dexmedetomidine and morphine but not xylazine on the capsaicin test are mainly due to spinal effects and that there is no synergistic interaction between dexmedetomidine and morphine in the neonatal rat.
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Brain Res. Dev. Brain Res. · May 2005
Comparative StudyPituitary adenylate cyclase-activating polypeptide (PACAP) can act as determinant of the tyrosine hydroxylase phenotype of dopaminergic cells during retina development.
In the chick retina, dopaminergic cells are generated between embryonic days 3 and 7 (E3/E7). However, the expression of tyrosine hydroxylase (TH), the first enzyme in the catecholamine synthetic pathway, is only detected after E11/E12. During the interval comprising E7 to E12, signals conveyed by cAMP are important to determine the TH phenotype. ⋯ Under this condition the amount of tyrosine hydroxylase expression, as detected by western blot analysis, was also increased. The protein kinase-A inhibitor, rp-cAMPS, significantly reduced the effect of PACAP. Our data show that this peptide is an important factor influencing the definition of the tyrosine hydroxylase phenotype of retina dopaminergic cells within a narrow window of development.
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Brain Res. Dev. Brain Res. · Feb 2005
Comparative StudyDistribution of RA175/TSLC1/SynCAM, a member of the immunoglobulin superfamily, in the developing nervous system.
RA175 is a new member of the immunoglobulin superfamily with trans interaction activity, and it plays a role as a tumor suppressor in lung carcinoma (TSLC1) and as a cell adhesion molecule promoting the formation of functional synapses (SynCAM). Little is known about the biological function of RA175/TSLC1/SynCAM neural network formation during neurogenesis. We examined the distribution and colocalization of the RA175/TSLC1/SynCAM protein with other members of the immunoglobulin superfamily such as NCAM, L1, and TAG-1 in the mouse developing nervous system. ⋯ In the E13.5-15.5 brain, RA175/TSLC1/SynCAM colocalized with NCAM and L1 on the developing thalamocortical fibers from the internal capsule (IC) and partly colocalized with TAG-1 on the cortical efferent axons in the intermediate zone (IZ). RA175/TSLC1/SynCAM was localized on the axons of some of the cortical neurons cultured in vitro. Thus, in addition to cell adhesion activity in the neuroepithelium and the synapses, RA175/TSLC1/SynCAM may be involved in neuronal migration, axon growth, pathfinding, and fasciculation on the axons of differentiating neurons.
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Brain Res. Dev. Brain Res. · Sep 2004
Long-term effects of seizures in neonatal rats on spatial learning ability and N-methyl-D-aspartate receptor expression in the brain.
For the purpose of investigating the long-term effects of seizures in neonatal rats on spatial learning ability and N-methyl-D-aspartate (NMDA) receptor expression in adult rat brain, a seizure was induced by inhalant flurothyl daily in neonatal Wistar rats from postnatal day 6 (P6). The authors assigned six rats each averagely into the single-seizure group, the recurrent-seizure group (seizures induced in six consecutive days), and the control group. During P60 to P65, the rats were tested for spatial learning ability with the Morris water maze task. ⋯ Compared with the control rats, the protein expressions of NR1, NR2A and NR2B in the cerebral cortex and NR2A in the hippocampus of the recurrent-seizure group was significantly decreased, but NR2C protein expression in the cerebral cortex and hippocampus significantly increased. Recurrent seizures induced in neonatal rats might cause long-term spatial learning ability deficit and modify NR expression in the cerebral cortex and hippocampus of adult rats. The results suggest that abnormal NR expression might play an important role in long-term spatial learning ability deficit induced by recurrent seizures in early life.