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We have previously shown that estradiol causes a twofold rise in dendritic spine density in cultured rat hippocampal neurons, as it does in vivo. More recently, estrogen receptors have been localized to aspiny inhibitory hippocampal interneurons, indicating that their effect on spiny pyramidal neurons may be indirect. We therefore examined the possibility(More)
We monitored developmental alterations in the morphology of dendritic spines in primary cultures of hippocampal neurons using confocal laser scanning microscopy (CLSM) and the fluorescent marker Dil. Dissociated rat hippocampal neurons were plated on polylysine-coated glass cover slips and grown in culture for 1-4 weeks. Fixed cultures were stained with Dil(More)
The role of afferent innervation in the formation of dendritic spines was studied in cultured rat striatum. The striatum is a unique structure in that it contains highly spiny GABAergic projection neurons, with no known local excitation. Grown alone in culture, striatal neurons did not express spontaneous network activity and were virtually devoid of(More)
The brain generates extensive spontaneous network activity patterns, even in the absence of extrinsic afferents. While the cognitive correlates of these complex activities are being unraveled, the rules that govern the generation, synchronization and spread of different patterns of intrinsic network activity in the brain are still enigmatic. Using(More)
Depletion of the forebrain serotonergic system was found in previous studies to induce an increased excitability of the dentate gyrus (DG) granule cells and, when combined with a cholinergic deficiency, to impair spatial learning. We now compared the effects of general forebrain serotonergic lesions induced by intracerebroventricular injection of(More)
Changes in cytosolic Na+ ([Na+]i) caused by a toxic glutamate (GLU) or NMDA treatment of cultured hippocampal neurons were monitored by using SBFI fluorescent probe and imaging microscopy. Both GLU and NMDA (50 or 100 microM in Mg(2+)-free solution, 15 min) induced a marked increase in [Na+]i (from 6-8 to 30-45 mM) which persisted after the termination of a(More)
Properties of the norepinephrine (NE) stimulated, cAMP-generating system were studied in rat hippocampal slices. NE but not other putative neurotransmitters, caused a 3--4-fold rise in cAMP levels in the slices. All 3 main subdivisions of the hippocampus (HPC), the dentate gyrus, areas CA3 and CA1, possessed the capacity to produce cAMP. The latency to the(More)
The recent finding that hippocampal slices from aged mice overexpressing the gene for superoxide dismutase (SOD) exhibit long-term potentiation (LTP) of reactivity to afferent stimulation that is significantly larger than that produced in aged wild-type (wt) mice has encouraged the exploration of the effects of reactive oxygen species (ROS) on learning in(More)
Using a newly developed method for quantitative acetylcholinesterase (AChE) histochemistry we find a substantial decrease in AChE content in aged rats compared to young controls in the cholinergic cell body regions (the ventral pallidum and the medial septal nuclei) and, to a smaller extent in the projection areas (the cortex and hippocampus). In the same(More)
Cholinergic M1 and M2 muscarinic receptors in aged and young rat brains were studied by quantitative autoradiography of tritiated QNB in the presence of pirenzepine or carbachol. A selective pattern of decreased binding density was observed in the aged rat. A large number of regions showed no effect of aging; these include subdivisions of the hippocampal(More)