Neuroscience
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Comparative Study
Exacerbated status epilepticus and acute cell loss, but no changes in epileptogenesis, in mice with increased brain-derived neurotrophic factor signaling.
Several studies suggest that brain-derived neurotrophic factor (BDNF) can exacerbate seizure development during status epilepticus (S. E.) and subsequent epileptogenesis in the adult brain. On the other hand, evidence exists for the protective effect of BDNF. ⋯ Our data support the role of BDNF and trkB signaling in seizure generation and acute cellular damage after S. E. Long-term outcome was not, however, exacerbated by trkB overexpression.
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Administration of typical and atypical antipsychotic drugs leads to activation of cells in the nucleus accumbens shell, central amygdaloid nucleus, and midline thalamic central medial nucleus, implicating important shared effects of these drugs. However, the exact cell types responding to antipsychotic drugs in the nucleus accumbens shell, central amygdaloid nucleus, and midline thalamic central medial nucleus are unclear. ⋯ The present study provides pharmacological evidence, at the cellular level in vivo, that the shared effects of antipsychotic drugs, whether typical and atypical, is activation of dynorphinergic GABA neurons in the nucleus accumbens shell, central amygdaloid nucleus, and midline thalamic central medial nucleus. Alternative ways to modulate dynorphinergic GABA neuronal activity or its target receptors might present an important new avenue for the treatment of schizophrenia and other psychotic disorders.
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Glutamate-mediated excitotoxicity might contribute to the pathogenesis of Huntington's disease and other polyglutamine repeat disorders. We used murine neocortical cultures derived from transgenic and knock-in mice to test the effect of expression of expanded polyglutamine-containing huntingtin on neuronal vulnerability to excitotoxins or other insults. ⋯ Neocortical neurons cultured from mice transgenic for an expanded CAG repeat-containing exon 1 of the human HD gene (Mangiarini et al., 1996, R6/2 line) and non-transgenic littermate controls also had similar vulnerability to NMDA and kainate-mediated excitotoxicity. These observations suggest that expression of expanded polyglutamine-containing huntingtin does not acutely alter the vulnerability of cortical neurons to excitotoxic, oxidative or apoptotic insults.
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Comparative Study
Effects of testosterone on hippocampal CA1 spine synaptic density in the male rat are inhibited by fimbria/fornix transection.
This study investigated the contribution of sub-cortical afferent input to the effects of testosterone (T) on spine synapse density in the CA1 subfield of the hippocampus, in adult male rats. Gonadectomized (GDX) male rats exhibited a considerably lower density of spine synapses in the CA1 region than control, intact males. ⋯ However, FF transection partially inhibited the responses to TP in GDX animals. These data suggest that the effects of T on spine synapse density in the CA1 region of the male rat hippocampus are partially, but not completely, dependent on afferent sub-cortical input.
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For peripheral iron to reach the brain, it must transverse the blood-brain barrier. In order for the brain to obtain iron, transferrin receptors are present in the vascular endothelial cell to facilitate movement of transferrin bound iron into the brain parenchyma. However, a number of significant voids exist in our knowledge about transport of iron into the brain. ⋯ Blocking pinocytosis had no effect on either transferrin or iron transcytosis. These results indicate that there is both transferrin-mediated and non-transferrin-mediated transcytosis of iron and that the process is influenced by the iron status of the cells. These data have considerable implications for common neurodegenerative diseases that are associated with excess brain iron accumulation and the numerous neurological complications associated with brain iron deficiency.