Fig. 1

Dopamine-mediated increase in IL-1β production in primary macrophages varies with expression of dopamine receptor subtypes. Primary human monocyte-derived macrophages (hMDM) were treated for 24 h with 10^–6 M dopamine. Lysates were collected and analyzed for IL-1β using AlphaLISAs. Results were normalized to protein concentration. qPCR detected mRNA for all subtypes of dopamine receptors (DRD1, DRD2, DRD3, DRD4 and DRD5). In our 42 donors, which together significantly respond to dopamine and increase IL-1β production (A), most express DRD1 and DRD2, whereas a much smaller proportion express DRD3 and DRD4 (B). The connection between dopamine receptors and IL-1β was determined by analysis of IL-1β levels in hMDM that did or did not express (C) DRD1, (D) DRD2, (E) DRD3, and (F) DRD4. Although all express DRD5, we examined DRD5’s impact on dopamine-induced IL-1β production by splitting expression into quartiles: low, medium, high, and highest expression (G). Significance was determined using Wilcoxon and Mann–Whitney tests, *p < 0.05, ***p < 0.001, and ****p < 0.0001