title: Oxytocin decreases sweet taste sensitivity in mice.
abstract: Oxytocin (OXT) suppresses food intake and lack of OXT leads to overconsumption of sucrose. Taste bud cells were recently discovered to express OXT-receptor. In the present study we tested whether administering OXT to wild-type mice affects their licking behavior for tastants in a paradigm designed to be sensitive to taste perception. We injected C57BL/6J mice intraperitoneally (i.p.) with 10mg/kg OXT and assayed their brief-access lick responses, motivated by water deprivation, to NaCl (300mM), citric acid (20mM), quinine (0.3mM), saccharin (10mM), and a mix of MSG and IMP (100mM and 0.5mM respectively). OXT had no effect on licking for NaCl, citric acid, or quinine. A possible effect of OXT on saccharin and MSG+IMP was difficult to interpret due to unexpectedly low lick rates to water (the vehicle for all taste solutions), likely caused by the use of a high OXT dose that suppressed licking and other behaviors. A subsequent experiment focused on another preferred tastant, sucrose, and employed a much lower OXT dose (0.1mg/kg). This modification, based on our measurements of plasma OXT following i.p. injection, permitted us to elevate plasma [OXT] sufficiently to preferentially activate taste bud cells. OXT at this low dose significantly reduced licking responses to 0.3M sucrose, and overall shifted the sucrose concentration - behavioral response curves rightward (mean EC50saline=0.362M vs. EC50OXT=0.466M). Males did not differ from females under any condition in this study. We propose that circulating oxytocin is another factor that modulates taste-based behavior.
authors.affiliation: Program in Neurosciences, University of Miami Miller School of Medicine, Miami, FL, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Sinclair
authors.affiliation: Department of Physiology & Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA.
authors.forename: Isabel
authors.initials: I
authors.lastname: Perea-Martinez
authors.affiliation: Department of Physiology & Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA.
authors.forename: Marianne
authors.initials: M
authors.lastname: Abouyared
authors.affiliation: Department of Psychology, Rollins College, Winter Park, FL, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: St John
authors.affiliation: Program in Neurosciences, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Physiology & Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA. Electronic address: NChaudhari@med.miami.edu.
authors.forename: Nirupa
authors.initials: N
authors.lastname: Chaudhari
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D019343:Citric Acid / Q000494:pharmacology; D005260:Female; D008297:Male; D051379:Mice; D010121:Oxytocin / Q000097:blood / Q000494:pharmacology*; D012439:Saccharin / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology; D013549:Sweetening Agents / Q000494:pharmacology*; D055697:Taste Perception / Q000187:drug effects*; D013652:Taste Threshold / Q000187:drug effects*
chemical_list: D013549:Sweetening Agents; D019343:Citric Acid; D012965:Sodium Chloride; D010121:Oxytocin; D012439:Saccharin
keywords: Brief-access test; Gustation; Licking; Oxytocin; Sweet