Long-term potentiation (LTP) is considered a cellular correlate of learning and memory. The presence of G protein-activated inwardly rectifying K(+) (GIRK) channels near excitatory synapses on dendritic spines suggests their possible involvement in synaptic plasticity. However, whether activity-dependent regulation of channels affects excitatory synaptic plasticity is unknown. In a companion article we have reported activity-dependent regulation of GIRK channel density in cultured hippocampal neurons that requires activity oF receptors (NMDAR) and protein phosphatase-1 (PP1) and takes place within 15 min. In this study, we performed whole-cell recordings of cultured hippocampal neurons and found that NMDAR activation increases basal GIRK current and GIRK channel activation mediated by adenosine A(1) receptors, but not GABA(B) receptors. Given the similar involvement of NMDARs, adenosine receptors, and PP1 in depotentiation of LTP caused by low-frequency stimulation that immediately follows LTP-inducing high-frequency stimulation, we wondered whether NMDAR-induced increase in GIRK channel surface density and current may contribute to the molecular mechanisms underlying this specific depotentiation. Remarkably, GIRK2 null mutation or GIRK channel blockade abolishes depotentiation of LTP, demonstrating that GIRK channels are critical for depotentiation, one form of excitatory synaptic plasticity.
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When there is a high concentration of positive transcription factors but a low affinity for the positive transcription factor
Transcription factors are proteins that regulate the transcription of genes—that is, their copying into RNA, on the way to making a protein.
Proteins called transcription factors, however, play a particularly central role in regulating transcription. These important proteins help determine which genes are active in each cell of your body.
<h3>How does transcription factors affect gene expression?</h3>
Under the influence of transcription factors, the various cells of the body can function differently though they have the same genome. Transcription factors attach to one or more series sites, which are called transcription element binding sites (TFBSs), binding to specific DNA sequences of the genes they control
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Calls Can Get Damaged, OR Age And Die. We Wouldn't Be "Us" If We Didn't Have Cells. Hope That Helps
It is the presence of oxygen-bound hemoglobin that makes it bright red