Early Activation of Extracellular Signal-Regulated Kinase Signaling Pathway in the Hippocampus is Required for Short-Term Memory Formation of a Fear-Motivated Learning

Abstract

1.S100B is a calcium-binding protein expressed and secreted by astrocytes, which has been implicated in glial-neuronal communication. Extracellular S100B appears to protect hippocampal neurons against toxic concentrations of glutamate. Here we investigated a possible autocrine role of S100B in glutamate uptake activity. 2. Astrocyte cultures were prepared of hippocampi from neonate Wistar rats. [(3)H] Glutamate uptake was measured after addition of S100B protein, antibody anti-S100B or TRTK-12, a peptide that blocks S100B activity mediated by the C-terminal region. 3.Antibody anti-S100B addition decreased glutamate uptake measured 30 min after medium replacement, without affecting cell integrity or viability. Moreover, low levels of S100B (less than 0.1 ng/mL) stimulated glutamate uptake measured immediately after medium replacement. 4. This finding reinforces the importance of astrocytes in the glutamatergic transmission, particularly the role of S100B neuroprotection against excitotoxic damage.

Oroxylin A enhances memory consolidation through the brain-derived neurotrophic factor in mice

“…Therefore, we conducted a receptor-binding assay and found that oroxylin A binds to GABA A (97% inhibition) and adenosine A2 A receptors (54% inhibition), which was also supported by several other findings (Kim et al, 2007;Jeon et al, 2012). It has been reported that GABA A receptor agonists suppress the activity of the MAPK pathway (Kalluri and Ticku, 2002;Igaz et al, 2006;Zheng et al, 2007) and that antagonists exert the opposite effect (Zheng et al, 2007;Kim et al, 2012). Moreover, adenosine A2 A receptor activation regulates BDNF production in rat cortical or hippocampal neurons (Diogenes et al, 2004;Jeon et al, 2011a).…”

Global view of the functional molecular organization of the avian cerebrum: Mirror images and functional columns

“…It has been noted that the 1 0 -pallium cells (IP) have some of the highest firing rates and genes involved in neuroprotection and Ca2 + buffering (Chew et al, 1995; Horita et al, 2010; Hara et al, 2012). Consistent with this idea, some new specializations we noted include S100B , a Ca2+ binding protein secreted by astrocytes that protects neurons against toxic concentrations of glutamate (Tramontina et al, 2006), and GRIK1 , which protects neurons that have overactivated NMDA receptors (Xu et al, 2008). The 2 0 -pallium regions (hyperpallium and nidopallium) are the only ones thus far without neurotransmitter receptor specializations (0 of 26 genes), despite us examining nearly all known vertebrate glutamate and dopamine receptors.…”

Serotonin 1A Receptors on Astrocytes as a Potential Target for the Treatment of Parkinson’s Disease

“…On the other hand, exposure to micromolar levels of S100β increases β−amyloid neurotoxicity [151] and causes neuronal apoptosis [152]. In addition, extracellular S100β at low dose enhances glutamate uptake activity of astrocytes, which plays essential roles in regulating extracellular levels of glutamate [153-155] (Fig. 2 ).…”

“…2 ). Tramontina et al [154, 155] provided direct evidence for the stimulatory effect of extracellular S100β on glutamate uptake into astrocytes by addition of S100β protein, and that anti-S100β antibody decreased glutamate uptake without affecting cell integrity or viability. It is also reported that epicatechin gallate, which is an abundant polyphenol in green tea, induces glutamate uptake and S100β secretion in astroglial C6 cells [153].…”