Acetylcholine in the brain.  I.  "Free," "bound" and total acetylcholine.
D000109:Acetylcholine / Q000378:metabolism*; D055592:Biophysical Phenomena; D001921:Brain / Q000378:metabolism*; D009435:Synaptic Transmission
D000109:Acetylcholine
ACETYLCHOLINE/metabolism; BRAIN/metabolism