title: Oral hydration, parotid salivation and the perceived pleasantness of small water volumes.
abstract: Previous studies have suggested that the preference for drinking cold water is increased when the drinker has a dry mouth. In a first experiment, we investigated whether a positive shift in preference would occur for small water volumes (0.75 ml and 1.5 ml) at 8, 16 or 25 degrees C, delivered into a mouth that had been dried using a warmed airflow, versus a normally hydrated mouth. Subjects rated the perceived wetness (or dryness) of their mouth, and the perceived pleasantness (or unpleasantness) of the water samples, using a labeled magnitude scale. Cooler water samples were preferred, and consistent with previous research, this preference was slightly enhanced when the subject's mouth was dried. The coldest water sample led to significantly wetter mouthfeel than the other two less cold samples, consistent with the possibility that the coldest water increased the rate of salivation. However, a second experiment found that although the rate of parotid salivation was increased if the mouth had been dried using a warm airflow, the different water temperatures did not induce different rates of parotid salivation. This indicates that enhanced preference for cold water when the mouth is dry is not invariably based in the reward gained from mouth rewetting via increased parotid saliva flow.
authors.affiliation: Center for Neurosensory Disorders, 2160 Old Dental Bldg., School of Dentistry, University of North Carolina, Chapel Hill, NC, USA. steve_guest@dentistry.unc.edu
authors.forename: Steve
authors.initials: S
authors.lastname: Guest
authors.forename: Greg
authors.initials: G
authors.lastname: Essick
authors.forename: Mike
authors.initials: M
authors.lastname: Young
authors.forename: Andy
authors.initials: A
authors.lastname: Lee
authors.forename: Nicola
authors.initials: N
authors.lastname: Phillips
authors.forename: Francis
authors.initials: F
authors.lastname: McGlone
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004305:Dose-Response Relationship, Drug; D005059:Euphoria / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D009055:Mouth / Q000187:drug effects* / Q000502:physiology; D010306:Parotid Gland / Q000378:metabolism*; D012472:Salivation / Q000187:drug effects / Q000502:physiology*; D013649:Taste / Q000502:physiology*; D013696:Temperature; D014867:Water / Q000494:pharmacology*
chemical_list: D014867:Water