Protocol for the measurement of secreted acetylcholine in the lumen of mouse intestine using LC-MS.

Acetylcholine (ACh) is a small-molecule neurotransmitter that regulates a wide range of neuronal and non-neuronal physiological functions. The non-neuronal roles of ACh are highly tissue specific, requiring precise measurements of its concentration in situ. Here, we present a protocol for measuring secreted ACh in the lumen of the mouse intestine. We describe the procedures for sample collection, preparation, and metabolite purification. Finally, we detail the use of liquid chromatography-mass spectrometry (LC-MS) to quantify ACh levels. For complete details on the use and execution of this protocol, please refer to Ndjim et al.(1).