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. 2020 Dec 21;46(7):1373–1385. doi: 10.1038/s41386-020-00927-x

Fig. 5. Transcriptional regulations induced in the striatum and amygdala of morphine abstinent mice by chronic facilitation of mGluR4 signaling.

Fig. 5

We evaluated the effects of chronic VU0155041 treatment (5 mg/kg) on transcriptional changes induced by morphine versus vehicle abstinence in the CPu, NAC, and CeA. We focused on the seven MSN marker genes (blue characters) highlighted in Fig. 1, Oxt and Avp coding for the social neuropeptides oxytocin and vasopressin, Fos as a marker of neuronal activity, and Bdnf and Syp as markers of synaptic plasticity. A Clustering analysis organized gene expression in 4 clusters per region. In the CPu and NAc, chronic VU0155041 restored (CPu: clusters b and c; NAc: clusters a, b,c) or increased (CPu: cluster a) the expression of most genes tested, which clustered with social parameters. In the CeA, rescued expression under VU0155041 treatment was observed in a single cluster (cluster b). B Among MSN marker genes highlighted in Fig. 1B, Drd1a and Hpca displayed significant down-regulation in the NAc, but not Arpp21, Gmr4, or Pde10a. VU0155041 rescued the expression of Drd1a and Hpca and increased the expression of Arpp21 and Grm4 in this region. Similarly, down-regulated expression of Oxt and Avp in the NAc of morphine-vehicle mice was rescued by VU0155041 treatment. Syp expression was increased upon VU0155041 exposure in the three regions tested. C Western blot analysis failed to detect modifications of synaptophysin (SYP) protein levels in the NAc, CPu and VTA but revealed a significant decrease in SYP immunoreactivity in the VP, (D) which represents the main projection area of NAc D2-MSNs. Gene (n = 9–10 per group) and protein (n = 8 per group) expression data are expressed as fold change versus vehicle-vehicle group for each condition (scatter plots and mean ± SEM). Comparison to vehicle-vehicle group: star p < 0.05 (two-tailed t-test, p value adjusted using Benjamin–Hochberg correction for multiple testing). Foll: number of following episodes, GASC: grooming after social contact, TNC: time in nose contact. qRT-PCR data used for clustering are displayed in Table S3.