Our latest work is now published in Frontiers in Behavioral Neuroscience!
Here, we demonstrate that both systemic and mPFC infusions of the muscarinic receptor antagonist scopolamine decreased the duration of licking bouts during access to high value sucrose solutions when provided alternating access to high and low value solutions. These results are similar to what has been previously reported following reversible inactivation of mPFC (Parent et al., 2015), and suggest that blocking mACh receptors with scopolamine disrupts the same elements of neuronal processing that is similarly affected by total cortical inactivation via muscimol. Exactly the opposite result was obtained when cholinergic tone was enhanced locally in mPFC with infusion of the cholinesterase inhibitor physostigmine (aka eserine), activation of mAChR with the mAChR agonist oxotremorine, and blocking KCNQ channels linked to mAChR receptors with XE-991. Furthermore, infusion of ghrelin, which acts on the same KCNQ channels as the muscarinic system enhanced the same measure of palatability (bout duration) only when the high value sucrose solution was available. The present study is the first to implicate cholinergic and ghrelinergic signaling in the mPFC, acting through KCNQ channels, in the expression of palatability.
