Striatal glutamate delta-1 receptor regulates behavioral flexibility and thalamostriatal connectivity

Ultrastructural localization of glutamate delta 1 (GluD1) receptor immunoreactivity in the mouse and monkey striatum

“…Because this analysis did not reveal any significant within‐group differences, quantitative data reported in Figure 4 are average percentages ± SEM of pooled data from three mice and three monkeys per group. Overall, the present findings from the mouse striatum confirm data from our recent study (Liu et al, 2020). In brief, GluD1 immunoreactivity in the mouse dorsal striatum was preferentially associated with dendritic shafts (47.9 ± 1.2% of total labeled structures) and glia (37.7 ± 2.5%), but significantly less abundant in dendritic spines (14.3 ± 2.6%) (Figure 4a).…”

“…The anatomical and functional interactions between striatal GluD1 and Pfstriatal terminals were further confirmed by recent data showing that vGluT2-containing thalamic terminals, but not vGuT1-positive cortical terminals, are in close contact with GluD1-immunoreactive striatal profiles (Liu et al, 2020). In addition, selective knock out of striatal GluD1 led to a profound loss of vGluT2-positive thalamostriatal terminals in mice (Liu et al, 2020). Altogether, these data provide a strong anatomical foundation for functional interactions between postsynaptic GluD1 and presynaptic Pf-striatal Cbln1 in the striatal matrix compartment, but they do not fully address the issue about the potential sources of presynaptic Cbln1 in the monkey striosomes.…”

“…All commercially available primary antibodies used in this study have been well characterized and are listed in the Research Resources Identifiers (RRIDs) Portal (Table 2). The specificity of the GluD1 antibody has been further validated in our previous study by the lack of staining in the striatum of GluD1 KO mice (Liu et al, 2020).…”

“…To determine if the relationships between vGluT1 or vGluT2 terminals and GluD1-immunoreactive profiles reported in our recent mouse study (Liu et al, 2020) was also seen in monkeys, we processed striatal tissue from one monkey for double immunofluorescence, and assessed the extent of colocalization between vGluT1-or vGluT2and GluD1-immunoreactive profiles in the monkey caudate nucleus.…”

“…Together, GluD2, Nxn, and Cbln1 help the development and maintenance of synapses through the formation of tripartite molecular complexes that anchor pre‐ and post‐synaptic elements (Uemura et al, 2010). There is evidence that Cbln1 and Nxn form such synaptic bridges with GluD1 in the mouse striatum (Krishnan et al, 2017; Liu et al, 2020; Yuzaki, 2018).…”