NR2B-containing N-methyl-D-aspartate subtype glutamate receptors regulate the acute stress effect on hippocampal long-term potentiation/long-term depression in vivo

Behavioral stress facilitates long-term depression but impairs long-term potentiation in the hippocampus. Recent evidence in vitro demonstrates that the NIR2B-containing N-methyl-D-aspartate subtype glutamate receptor antagonist Ro25-6981 prevents the beh

N-methyl-D-aspartate receptor-dependent long-term potentiation in CA1 region affects synaptic expression of glutamate receptor subunits and associated proteins in the whole hippocampus

Long term potentiation in hippocampus, evoked by high-frequency stimulation, is mediated by two major glutamate receptor subtypes, alpha-amino-3-hydroxyl-5-methyl-4-isoxazole propionate receptors and N-methyl-D-aspartate receptors. Receptor subunit compos

Acute behavioural stress facilitates long-term depression in temporoammonic-CAI pathway

Behavioural stress facilitates long-term depression in Schaffer collaterals-CAI pathway, but it is unknown whether it influences long-term depression in temporoammonic fibres-CAI. Here, we report that low-frequency stimulation induced long-term depression

Exposure to chronic constant light impairs spatial memory and influences long-term depression in rats

Exposure to chronic constant light (CCL) influences circadian rhythms and evokes stress. Since hippocampus is sensitive to stress, which facilitates long-term depression (LTD) in the hippocampal CA1 area, we examined whether CCL exposure influenced hippoc

GABA Transporter-1 Activity Modulates Hippocampal Theta Oscillation and Theta Burst Stimulation-Induced Long-Term Potentiation

The network oscillation and synaptic plasticity are known to be regulated by GABAergic inhibition, but how they are affected by changes in the GABA transporter activity remains unclear. Here we show that in the CA1 region of mouse hippocampus, pharmacolog

Chronic Morphine Treatment Impaired Hippocampal Long-Term Potentiation and Spatial Memory via Accumulation of Extracellular Adenosine Acting on Adenosine A(1) Receptors

Chronic exposure to opiates impairs hippocampal long-term potentiation (LTP) and spatial memory, but the underlying mechanisms remain to be elucidated. Given the well known effects of adenosine, an important neuromodulator, on hippocampal neuronal excitability and synaptic plasticity, we investigated the potential effect of changes in adenosine concentrations on chronic morphine treatment-induced impairment of hippocampal CA1 LTP and spatial memory. We found that chronic treatment in mice with either increasing doses (20-100 mg/kg) of morphine for 7 d or equal daily dose (20 mg/kg) of morphine for 12 d led to a significant increase of hippocampal extracellular adenosine concentrations. Importantly, we found that accumulated adenosine contributed to the inhibition of the hippocampal CA1 LTP and impairment of spatial memory retrieval measured in the Morris water maze. Adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine significantly reversed chronic morphine-induced impairment of hippocampal CA1 LTP and spatial memory. Likewise, adenosine deaminase, which converts adenosine into the inactive metabolite inosine, restored impaired hippocampal CA1 LTP. We further found that adenosine accumulation was attributable to the alteration of adenosine uptake but not adenosine metabolisms. Bidirectional nucleoside transporters (ENT2) appeared to play a key role in the reduction of adenosine uptake. Changes in PKC-alpha/beta activity were correlated with the attenuation of the ENT2 function in the short-term (2 h) but not in the long-term (7 d) period after the termination of morphine treatment. This study reveals a potential mechanism by which chronic exposure to morphine leads to impairment of both hippocampal LTP and spatial memory.

Energy efficiency, resilience to future climates and long-term sustainability: the role of the built environment

Just under half of all energy consumption in the UK today takes place indoors, and over a quarter within our homes. The challenges associated with energy security, climate change and sustainable consumption will be overcome or lost in existing buildings. A background analysis, and the scale of the engineering challenge for the next three to four decades, is described in this paper.

Energy efficiency, resilience to future climates and long-term sustainability: the role of the built environment.

Just under half of all energy consumption in the UK today takes place indoors, and over a quarter within our homes. The challenges associated with energy security, climate change and sustainable consumption will be overcome or lost in our existing buildings. A background analysis, and the scale of the engineering challenge for the next three to four decades, is described in this paper.

Centrifuge modelling on long-term behaviour of tunnels in transitional ground

Long-term settlement of tunnels has caused concerns about its influence on tunnel safety and serviceability. Aiming to investigate the long-term behaviour of tunnels against the background of Shanghai metro line, two cases of centrifuge modelling were conducted, with efforts to expose the mechanism affecting the consolidation of the ground. Evenly layered ground and transitional ground strata were set for each case separately and the settlement, lining load and pore water pressure were checked against elapsed time up to 20 years. The results verified some previous findings concerning the settlement and lining load development trend, however, it was also shown that the transitional ground made the tunnel response more complicated. The research is expected to provide some basis for further research on other affecting factors, such as lining permeability. © 2010 Taylor & Francis Group, London.