title: A specific multi-nutrient formulation enhances M1 muscarinic acetylcholine receptor responses in vitro.
abstract: Recent evidence indicates that supplementation with a specific combination of nutrients may affect cell membrane synthesis and composition. To investigate whether such nutrients may also modify the physical properties of membranes, and affect membrane-bound processes involved in signal transduction pathways, we studied the effects of nutrient supplementation on G protein-coupled receptor activation in vitro. In particular, we investigated muscarinic receptors, which are important for the progression of memory deterioration and pathology of Alzheimer's disease. Nerve growth factor differentiated pheochromocytoma cells that were supplemented with specific combinations of nutrients showed enhanced responses to muscarinic receptor agonists in a membrane potential assay. The largest effects were obtained with a combination of nutrients known as Fortasyn™ Connect, comprising docosahexaenoic acid, eicosapentaenoic acid, uridine monophosphate as a uridine source, choline, vitamin B6, vitamin B12, folic acid, phospholipids, vitamin C, vitamin E, and selenium. In subsequent experiments, it was shown that the effects of supplementation could not be attributed to single nutrients. In addition, it was shown that the agonist-induced response and the supplement-induced enhancement of the response were blocked with the muscarinic receptor antagonists atropine, telenzepine, and AF-DX 384. In order to determine whether the effects of Fortasyn™ Connect supplementation were receptor subtype specific, we investigated binding properties and activation of human muscarinic M1, M2 and M4 receptors in stably transfected Chinese hamster ovary cells after supplementation. Multi-nutrient supplementation did not change M1 receptor density in plasma membranes. However, M1 receptor-mediated G protein activation was significantly enhanced. In contrast, supplementation of M2- or M4-expressing cells did not affect receptor signaling. Taken together, these results indicate that a specific combination of nutrients acts synergistically in enhancing muscarinic M1 receptor responses, probably by facilitating receptor-mediated G protein activation.
authors.affiliation: Nutricia Advanced Medical Nutrition, Danone Research, Centre for Specialised Nutrition, Wageningen, The Netherlands. paul.savelkoul@danone.com
authors.forename: Paul J M
authors.initials: PJ
authors.lastname: Savelkoul
authors.forename: Helena
authors.initials: H
authors.lastname: Janickova
authors.forename: Almar A M
authors.initials: AA
authors.lastname: Kuipers
authors.forename: Robert J J
authors.initials: RJ
authors.lastname: Hageman
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Kamphuis
authors.forename: Vladimir
authors.initials: V
authors.lastname: Dolezal
authors.forename: Laus M
authors.initials: LM
authors.lastname: Broersen
mesh_terms: D000818:Animals; D016466:CHO Cells; D002217:Carbachol / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D019204:GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D018977:Micronutrients / Q000737:chemistry / Q000494:pharmacology*; D016716:PC12 Cells; D011485:Protein Binding; D051381:Rats; D043643:Receptor, Muscarinic M1 / Q000819:agonists / Q000502:physiology*; D015854:Up-Regulation / Q000502:physiology*
chemical_list: D018977:Micronutrients; D043643:Receptor, Muscarinic M1; D002217:Carbachol; D019204:GTP-Binding Proteins