Microglial receptor for advanced glycation end product-dependent signal pathway drives beta-amyloid-induced synaptic depression and long-term depression impairment in entorhinal cortex.

Overproduction of beta-amyloid (Abeta) is a pathologic feature of Alzheimer's disease, leading to cognitive impairment. Here, we investigated the impact of cell-specific receptor for advanced glycation end products (RAGE) on Abeta-induced entorhinal cortex (EC) synaptic dysfunction. We found both a transient depression of basal synaptic transmission and inhibition of long-term depression (LTD) after the application of Abeta in EC slices.

Phosphodiesterase 5 inhibition improves synaptic function, memory, and amyloid-beta load in an Alzheimer's disease mouse model.

Memory loss, synaptic dysfunction, and accumulation of amyloid beta-peptides (A beta) are major hallmarks of Alzheimer's disease (AD). Downregulation of the nitric oxide/cGMP/cGMP-dependent protein kinase/c-AMP responsive element-binding protein (CREB) cascade has been linked to the synaptic deficits after A beta elevation. Here, we report that the phosphodiesterase 5 inhibitor (PDE5) sildenafil (Viagra), a molecule that enhances phosphorylation of CREB, a molecule involved in memory, through elevation of cGMP levels, is beneficial against the AD phenotype in a mouse model of amyloid deposition.

Picomolar amyloid-beta positively modulates synaptic plasticity and memory in hippocampus.

Amyloid-beta (Abeta) peptides are produced in high amounts during Alzheimer's disease, causing synaptic and memory dysfunction. However, they are also released in lower amounts in normal brains throughout life during synaptic activity. Here we show that low picomolar concentrations of a preparation containing both Abeta(42) monomers and oligomers cause a marked increase of hippocampal long-term potentiation, whereas high nanomolar concentrations lead to the well established reduction of potentiation.

The role of ubiquitin C-terminal hydrolase L1 in neurodegenerative disorders.

Impairment of the ubiquitin-proteasome system (UPS) results in the failure to remove and degrade misfolded proteins and consequently causes the accumulation of misfolded proteins in the cell. The aberrant interactions between misfolded proteins and normal intracellular proteins are thought to underlie the pathogenesis in many neurodegenerative diseases. Ubiquitin C-terminal hydrolase L1 (UCH-L1) is an important component of the UPS.

Modafinil enhances thalamocortical activity by increasing neuronal electrotonic coupling.

Modafinil (Provigil, Modiodal), an antinarcoleptic and mood-enhancing drug, is shown here to sharpen thalamocortical activity and to increase electrical coupling between cortical interneurons and between nerve cells in the inferior olivary nucleus. After irreversible pharmacological block of connexin permeability (i.e.

Role of gap junctions in synchronized neuronal oscillations in the inferior olive.

Inferior olivary (IO) neurons are electrically coupled through gap junctions and generate synchronous subthreshold oscillations of their membrane potential at a frequency of 1-10 Hz. Whereas the ionic mechanisms of these oscillatory responses are well understood, their origin and ensemble properties remain controversial. Here, the role of gap junctions in generating and synchronizing IO oscillations was examined by combining intracellular recordings with high-speed voltage-sensitive dye imaging in rat brain stem slices.

Rhythmic and dysrhythmic thalamocortical dynamics: GABA systems and the edge effect.

Brain function is fundamentally related in the most general sense to the richness of thalamocortical interconnectivity, and in particular to the rhythmic oscillatory properties of thalamocortical loops. Such rhythmicity is involved in the genesis of cognition, in the sleep-wake cycle, and in several neurological and psychiatric disorders. The role of GABA-mediated transmission in regulating these functional states is addressed here.

Electrotonically mediated oscillatory patterns in neuronal ensembles: an in vitro voltage-dependent dye-imaging study in the inferior olive.

Spatiotemporal profiles of ensemble subthreshold neuronal oscillation were studied in brainstem slices using high-speed voltage-sensitive dye imaging. After local electrical stimuli, the overall voltage profile demonstrated coherent oscillatory waves that spread over the inferior olive (IO). These oscillations were also observed in concurrently obtained intracellular recordings from IO neurons.

Temporal binding via cortical coincidence detection of specific and nonspecific thalamocortical inputs: a voltage-dependent dye-imaging study in mouse brain slices.

Voltage-sensitive dye imaging of mouse thalamocortical slices demonstrated that electrical stimulation of the centrolateral intralaminar thalamic nucleus (CL) resulted in the specific activation of thalamic reticular nucleus, striatum/putamen, and cortical layers 5, 6, and 1. By contrast, ventrobasal (VB) thalamic stimulation, while activating the reticular and basal ganglia nuclei, also activated directly layers 4 and deep 5 of the cortex. Conjoined stimulation of the VB and CL nuclei resulted in supralinear summation of the two inputs at cortical output layer 5, demonstrating coincidence detection along the apical dendrites.