JCI: Chemogenetic (and other approaches) interrogate inflammation-associated aversion in DA neurons

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.

Paper here

Comments

Post a Comment

Popular posts from this blog

CNO in drinking water

We frequently get requests regarding protocols for putting CNO in the drinking water for long-term studies. Here is our protocol: 1. Dissolve the CNO in a small volume of DMSO 2. Diluted the dissolved CNO in drinking water (e.g., 5mg/200ml) 3. Give mice with CNO drinking water  and protect from light using foil-wrapped bottles 4. The mice will receive 5mg/kg/day CNO (assume that mice weight 30g and consume 6ml water per day) 5. Prepare fresh daily. 6. A small amount of saccharine in the drinking water will mask the slightly bitter taste of CNO
Read more

How best to dissolve CNO ...it depends on what it is soluble in (and that depends on the particular polymorph)

I recently received the following question: " My question is with regard to the use of CNO in drinking water (in mouse studies). Your recipe calls for the addition of a small amount of DMSO to dissolve CNO at a concentration of 5 mg in 200 mL. As we and others routinely dissolve CNO in 0.9% saline (no DMSO) at concentrations up to four times this amount, I am curious whether the addition of DMSO to CNO solutions for H2O drinking is critical, or whether the properties of CNO permit it's direct dissolution in H2O at concentrations from 5-20 mg per 200 mL. There appears to be no difficulty dissolving such concentrations in H2O in my hands, but I would prefer to hear your perspective. Is there a published reference for the solubility profile of CNO in H2O or 0.9% saline?" It basically depends upon the source of the CNO.  CNO via the NIH RAID program (which is what we use) is not readily soluble in H20 while commercial CNO is.  Although we've verified that both source
Read more