Journal of Clinical Investigation 2016-02-01

Prostaglandin-dependent modulation of dopaminergic neurotransmission elicits inflammation-induced aversion in mice.

Michael Fritz, Anna M Klawonn, Anna Nilsson, Anand Kumar Singh, Joanna Zajdel, Daniel Björk Wilhelms, Michael Lazarus, Andreas Löfberg, Maarit Jaarola, Unn Örtegren Kugelberg, Timothy R Billiar, David J Hackam, Chhinder P Sodhi, Matthew D Breyer, Johan Jakobsson, Markus Schwaninger, Günther Schütz, Jan Rodriguez Parkitna, Clifford B Saper, Anders Blomqvist, David Engblom

文献索引：J. Clin. Invest. 126 , 695-705, (2016)

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摘要

Systemic inflammation causes malaise and general feelings of discomfort. This fundamental aspect of the sickness response reduces the quality of life for people suffering from chronic inflammatory diseases and is a nuisance during mild infections like common colds or the flu. To investigate how inflammation is perceived as unpleasant and causes negative affect, we used a behavioral test in which mice avoid an environment that they have learned to associate with inflammation-induced discomfort. Using a combination of cell-type–specific gene deletions, pharmacology, and chemogenetics, we found that systemic inflammation triggered aversion through MyD88-dependent activation of the brain endothelium followed by COX1-mediated cerebral prostaglandin E2 (PGE2) synthesis. Further, we showed that inflammation-induced PGE2 targeted EP1 receptors on striatal dopamine D1 receptor–expressing neurons and that this signaling sequence induced aversion through GABA-mediated inhibition of dopaminergic cells. Finally, we demonstrated that inflammation-induced aversion was not an indirect consequence of fever or anorexia but that it constituted an independent inflammatory symptom triggered by a unique molecular mechanism. Collectively, these findings demonstrate that PGE2-mediated modulation of the dopaminergic motivational circuitry is a key mechanism underlying the negative affect induced by inflammation.