title: Analysis of free ACh and 5-HT in milk from four different species and their bioactivity on 5-HT(3) and nACh receptors.
abstract: Milk is one of the most beneficial aliments and is highly recommended in normal conditions; however, in certain disorders, like irritable bowel syndrome, cow milk and dairy products worsen the gastric symptoms and their use is not recommended. Among the most recognized milk-induced gatrointestinal symptoms are abdominal pain, nausea and vomiting, which are processes controlled by cholinergic and serotonergic transmission. Whether the presence of bioavailable ACh and 5-HT in milk may contribute to normal peristalsis, or to the developing of these symptoms, is not known. In this work we attempt to determine whether the content of free ACh and 5-HT is of physiological significance in milk from four different species: cow (bovine), goat, camel and human. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to identify and quantify free ACh and 5-HT in milk, and activation of the serotonergic and cholinergic ionotropic receptors was investigated using electrophysiological experiments. Our principal hypothesis was that milk from these four species had sufficient free ACh and 5-HT to activate their correspondent receptors expressed in a heterologous system. Our results showed a more complex picture, in which free ACh and 5-HT and their ability to activate cholinergic and serotonergic receptors are not correlated. This work is a first step to elucidate whether 5-HT and ACh, at the concentrations present in the milk, can be associated to a direct function in the GI.
authors.affiliation: Department of Neurobiology and Behavior, University of California, 2205 McGaugh Hall, Irvine, CA 92697, USA. rmiledi@uci.edu alimonru@uci.edu.
authors.forename: Jose-Luis
authors.initials: JL
authors.lastname: Gallegos-Perez
authors.forename: Agenor
authors.initials: A
authors.lastname: Limon
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Reyes-Ruiz
authors.forename: Ali S
authors.initials: AS
authors.lastname: Alshanqeeti
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Aljohi
authors.forename: Ricardo
authors.initials: R
authors.lastname: Miledi
mesh_terms: D000109:Acetylcholine / Q000032:analysis*; D000818:Animals; D002162:Camelus; D002417:Cattle; D018678:Cholinergic Agents / Q000494:pharmacology; D002853:Chromatography, Liquid; D006041:Goats; D006801:Humans; D008892:Milk / Q000737:chemistry*; D008895:Milk, Human / Q000737:chemistry*; D011950:Receptors, Cholinergic / Q000378:metabolism; D011985:Receptors, Serotonin / Q000378:metabolism; D012701:Serotonin / Q000032:analysis*; D053719:Tandem Mass Spectrometry
chemical_list: D018678:Cholinergic Agents; D011950:Receptors, Cholinergic; D011985:Receptors, Serotonin; D012701:Serotonin; D000109:Acetylcholine