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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The types of evidence for evolution include
i) Changes in allele frequency over subsequent generations.
ii) When the population in question is examined it does not follow Hardy-Weiberg equilibrium.
iii) Signs of gene flow between populations.
iv) Presence of Sewall-Wright effects or genetic drift in the population.
Please mark as brainliest.
Answer:
Option (1).
Explanation:
DNA (deoxyribo nucleic acid ) is the genetic material present in all the organisms except some viruses. DNA structure follows the Chargaff's rule.
Accoprding to Chargaff's rule, the ratio of purines to pyrimidines in a DNA molecule is equal to 1. The amount of guanine is nearly equal to the amount of cytosine whereas the amount of thymine is nearly equal to the amount of adenine.
Thus, the correct answer is option (1).
Dumb isn’t necessarily a human characteristic. i suppose it will depend on the context.
