It's interesting that "The M3 muscarinic receptor regulates fear and learning.." and "M3-muscarinic receptor knockout mice show a deficit in fear conditioning l

It's interesting that "The M3 muscarinic receptor regulates fear and learning.." and "M3-muscarinic receptor knockout mice show a deficit in fear conditioning learning and memory". https://www.pnas.org/doi/10.1073/pnas.0914801107 https://www.pnas.org/doi/10.1073/pnas.0914801107 "We demonstrate here that M3-muscarinic receptor knockout mice show a deficit in fear conditioning learning and memory." It's interesting the Mucinex antagonizes the M3 receptor. Behavioral effects of Mucinex are very understudied. M3 receptors also classically handle lung "learning" and response to allergens. https://pubmed.ncbi.nlm.nih.gov/8441331/ https://pubmed.ncbi.nlm.nih.gov/8441331/ - "Muscarinic receptor subtypes in airways"