NMDARs are glutamate-gated
ion channels involved in excitatory synaptic transmission, synaptic plasticity, and excitotoxicity. To determine the mechanism that controls PS sensitivity of NMDARs, we measured NMDAR responses induced by exogenous agonist application in voltage-clamped HEK293 cells expressing NR1/NR2B NMDARs and cultured rat hippocampal neurons. We report that PS potentiates the amplitude of whole-cell recorded NMDAR responses in cultured hippocampal neurons and HEK293 cells; however, the potentiating effect of PS on NMDAR in outside-out patches isolated from cultured hippocampal neurons and HEK293 cells was lost within 2 min after patch isolation in a neurosteroid-specific manner. The rate of diminution of the PS potentiating effect was slowed by Adriamycin molecular weight protein phosphatase inhibitors. Treatment of cultured hippocampal neurons with a nonspecific protein kinase inhibitor and a specific protein kinase A (PKA) inhibitor diminished PS-induced potentiation, which was recovered by adding a PKA, but not a protein kinase C (PKC), activator. These results suggest that the effect of PS on NMDARs is controlled by cellular mechanisms that are mediated by dephosphorylation/phosphorylation pathways. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.”
“To investigate the effects check details of the medium and cryoprotective agents
used on the growth and survival of Lactobacillus plantarum and Lactobacillus rhamnosus GG during freeze drying.
A complex medium was developed consisting primarily of glucose, yeast extract and vegetable-derived peptone. Trehalose, sucrose and sorbitol were examined for their ability to protect the cells during freeze drying. Using standardized amount of cells and the optimized freeze drying media, the effect of the growth medium on cell survival during freeze drying was investigated. The results showed that glucose and yeast extract were the most others important growth factors, while sucrose offered better protection than trehalose and sorbitol during freeze drying. When the cells
were grown under carbon limiting conditions, their survival during freeze drying was significantly decreased.
A clear relationship was observed between cell growth and the ability of the cells to survive during the freeze drying process.
The survival of probiotic strains during freeze drying was shown to be dependent on the cryoprotectant used and the growth medium.”
“The impact of juvenile stress exposure on astrocyte plasticity was assessed in the precocious rodent Octodon degus. Astrocytes expressing S100 beta and glial fibrillary acidic protein (GFAP) were quantified in the limbic medial prefrontal cortex (mPFC), including the anterior cingulate (ACd), precentral medial (PrCm), infra- (IL) and prelimbic (PL) cortex and in the “”non-limbic”" somatosensory cortex (SSC).