Figure 1: LH syndecan-3 is induced by cocaine.

(a) Syndecan-3 is induced by cocaine intake in the LH, but not in the NAc of cocaine-self-administering rats as measured by quantitative real-time PCR (qRT-PCR) with the standard curve method normalizing to β-actin (n=4–5). Units on the y axis represent the ratios of syndecan mRNA levels to that of β-actin in each region (*P<0.05, by one-way ANOVA with Tukey’s post-hoc test). (b) GSEA indicates that genes related to syndecan-3-dependent signaling are enriched in differentially expressed genes in the LH of cocaine-self-administering rats compared with control rats (normalized enrichment score, NES=1.9; P<0.001). The dotted line, also called leading edge, indicates the point at which the running enrichment score reaches its maximum score. (c) Cocaine increases the expression of syndecan-3 mRNA in the LH but not in the NAc of mice after six daily IP administrations of 18 mg kg⁻¹ of cocaine; control mice received isovolemic injections of saline vehicle (n=5; **P<0.01 by t-test). (d) Syndecan-3 mRNA is increased in the LH in cocaine-self-administering macaques (n=4; *P<0.05 by t-test). Data are presented as mean±s.e.m.