intrinsic plasticity of nigrostriatal click here DAergic neurons and deciphering the signals facilitating the crosstalk between astrocytes, microglia, DAergic neurons and NPCs may have major implications for the role of stem cell technology in PD, and for identifying potential therapeutic targets to induce endogenous neurorepair. “
“Cannabinoid receptor 1 (CB1 receptor) controls several neuronal functions, including neurotransmitter release, synaptic plasticity, gene expression and neuronal viability. Downregulation of CB1 expression in the basal ganglia of patients with Huntington’s disease (HD) and animal models represents one of the earliest molecular events induced by mutant huntingtin (mHtt). This early disruption of neuronal CB1 signaling is thought to contribute to HD symptoms and neurodegeneration. Here we determined www.selleckchem.com/PARP.html whether CB1 downregulation measured in patients with HD and mouse models was ubiquitous or restricted to specific striatal neuronal subpopulations. Using unbiased semi-quantitative immunohistochemistry, we confirmed previous studies showing that CB1 expression is downregulated in medium spiny neurons of the indirect pathway, and found that CB1 is also downregulated in neuropeptide Y (NPY)/neuronal nitric oxide synthase (nNOS)-expressing interneurons while remaining unchanged in parvalbumin- and calretinin-expressing interneurons.
CB1 downregulation in striatal NPY/nNOS-expressing interneurons occurs in R6/2 mice, HdhQ150/Q150 mice and the caudate nucleus of patients with HD. In R6/2 mice, CB1 downregulation in NPY/nNOS-expressing interneurons correlates with diffuse expression of mHtt in the soma. This downregulation also occludes the ability of cannabinoid agonists to activate the pro-survival signaling molecule cAMP response element-binding protein in NPY/nNOS-expressing interneurons. Loss of CB1 signaling in NPY/nNOS-expressing interneurons could contribute to the impairment of basal ganglia functions linked to HD. “
“MicroRNAs comprise single-stranded RNA molecules of 19–24 nucleotides
in length (Lee et al., 1993; Lagos-Quintana stiripentol et al., 2001). They are not translated into protein; rather they typically downregulate gene expression. MicroRNAs play a very dominant role in gene-regulation (Bartel, 2001), but as yet little is known about their possible contribution to processes underlying synaptic plasticity. Given that synaptic plasticity is believed to underlie memory formation (Morris et al., 2003; Kemp & Manahan-Vaughan, 2007), and the fact that forms of long-lasting synaptic plasticity depend on protein synthesis (Frey et al., 1988; Manahan-Vaughan et al., 2000), it is tempting to suspect that microRNAs may indeed be important for this phenomenon. This was the subject of the study conducted by Wibrand et al. (2010) that is reported in the current issue of EJN.