Estrogens have long been implicated in influencing cognitive processes, yet the molecular mechanisms underlying these effects and the roles of the estrogen receptors alpha (ERalpha) and beta (ERbeta) remain unclear. Using pharmacological, biochemical and behavioral techniques, we demonstrate that the effects of estrogen on hippocampal synaptic plasticity and memory are mediated through ERbeta. Selective ERbeta agonists increased key synaptic proteins in vivo, including PSD-95, synaptophysin and the AMPA-receptor subunit GluR1. These effects were absent in ERbeta knockout mice. In hippocampal slices, ERbeta activation enhanced long-term potentiation, an effect that was absent in slices from ERbeta knockout mice. ERbeta activation induced morphological changes in hippocampal neurons in vivo, including increased dendritic branching and increased density of mushroom-type spines. An ERbeta agonist, but not an ERalpha agonist, also improved performance in hippocampus-dependent memory tasks. Our data suggest that activation of ERbeta can regulate hippocampal synaptic plasticity and improve hippocampus-dependent cognition.

Astrocytes are the most populous glial subtype and are critical for brain function. Despite this, historically there have been few studies into the role that they may have in neurodegenerative diseases, such as Parkinson’s disease (PD). Recently, however, several studies have determined that genes known to have a causative role in the development of PD are expressed in astrocytes and have important roles in astrocyte function. Here, we review these recent developments and discuss their impact on our understanding of the pathophysiology of PD, and the implications that this might have for its treatment.

6-[(3-Cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-yl)oxy]-N-methyl-3-pyridinecarboxamide hydrochloride (GSK189254) is a novel histamine H 3 receptor antagonist with high affinity for human (pK i ϭ 9.59 -9.90) and rat (pK i ϭ 8.51-9.17) H 3 receptors. GSK189254 is Ͼ10,000-fold selective for human H 3 receptors versus other targets tested, and it exhibited potent functional antagonism (pA 2 ϭ 9.06 versus agonist-induced changes in cAMP) and inverse agonism [pIC 50 Progressive decline in cognitive performance is a key characteristic of Alzheimer's disease (AD) and related dementias, and improving cognitive function in these diseases represents a complex challenge, given the involvement of numerous neurotransmitter systems and brain regions (CoreyBloom, 2002). Current therapies, such as cholinesterase inhibitors, provide only minimal benefit to a subset of patients and for a limited period, so a number of alternative Article, publication date, and citation information can be found at

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Background: LRRK2 kinase activity has been implicated in Parkinson disease (PD). Results: LRRK2 kinase inhibition attenuated neurodegeneration in LRRK2 transgenic and wild-type rats. Conclusion: Chronic inhibition of LRRK2 kinase activity is well tolerated in rats and provides neuroprotection from ␣-synuclein overexpression. Significance: These results warrant further studies that test the therapeutic potential of LRRK2 kinase inhibitors in additional PD models.