[The role of dopamine receptors in the modulation of mononuclear phagocytes in multiple sclerosis].

Abstract

Objective: To investigate the role of dopamine receptor D₁DR and D₂DR in the production of cytokines interleukin-6 (IL-6) and IL-1β by monocytes and macrophages in patients with relapsing-remitting multiple sclerosis (MS).

Material and methods: Ten patients with relapsing-remitting MS and 10 healthy subjects were examined. The level of IL-6 and IL-1β production was assessed in culture supernatants obtained from CD14⁺ monocytes or macrophages stimulated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS). To study the role of dopamine receptors in the regulation of CD14⁺ monocytes or macrophages, samples of cells were incubated in the presence of specific D₁DR or D₂DR antagonists, after which IFN-γ/LPS were added to the cultures. Levels of cytokines in culture supernatants were measured by enzyme-linked immunosorbent assay.

Results: The production of IL-6 and IL-1β by CD14⁺ monocytes and macrophages was comparable between the groups. Blockade of D₁DR suppressed cytokine production by CD14⁺ monocytes and macrophages in both groups. In contrast, blockade of D₂DR increased the production of cytokines by CD14⁺ monocytes and did not affect cytokine production by macrophages in both groups.

Conclusions: Targeting of dopaminergic receptors could be considered as an additional mechanism of immunomodulation in MS with both pro- and anti-inflammatory effects on cells of the innate immune system.