4. Discussion
We have investigated whether expression of ArcKR, a form of Arc where the major ubiquitination sites have been mutated, and its degradation is slowed, (Mabb et al. , 2014; Wall et al. , 2018) affects synaptic plasticity in area CA1 of the hippocampus. In particular, we have investigated the effects of ArcKR expression on long-term potentiation (LTP) and whether priming of mGluR affects LTP in this mouse. In agreement with our previous study (Wall et al. , 2018), we found that SC-CA1 basal synaptic transmission was not significantly different in standard housed adult ArcKR mice compared to WT mice. We also showed that, like DHPG-induced- LTD (Wallet al. , 2018), synaptically-induced paired-pulse low frequency stimulation (PP-LFS)-induced mGluR-LTD was significantly enhanced in ArcKR mice. Corroborating the idea that transient increase in Arc expression levels facilitate PP-LFS-mediated LTD is the observation that Arc mRNA and protein expression, as well as PP-LFS mediated LTD are increased in the hippocampus in the APP/PS1 mouse at 7 months of age (Privitera et al. , 2022).