Figure 1.

CB1 expression is upregulated during homeostatic downscaling in mature neurons. A, Representative Western blottings of surface and total protein expression in developing (DIV10–DIV12) and mature (DIV21–DIV25) cultured cortical neurons treated for 48 h with control media (Ctrl), 20 μm bicuculline (BCC), or 1 μm tetrodotoxin (TTX). B, C, Quantification of data shown in A in developing neurons (B) and mature neurons (C). BCC induced downregulation of surface GluA1 and dephosphorylation of S845 regardless of age, but upregulation of total and surface CB1 only in mature neurons. Results were normalized for each protein to its expression under control levels and presented as mean ± SEM from at least three independent culture preparations with triplicate wells. D, E, Representative Western blottings and quantification of total protein expression in cultured cortical neurons at DIV8, DIV15, and DIV22. Results are normalized for each protein to its expression levels at DIV15, and presented as mean ± SEM from at least three independent culture preparations with quadruplicate wells. Standard unpaired t test was used for B, C and one-way ANOVA with Dunnett’s multiple comparison test was used for E; *p ≤ 0.05, **p ≤ 0.01. ns = not significant.