The role of sucrose-sensitive neurons in ingestion of sweet stimuli by hamsters.
The relationship between sweet preference and activity in sucrose-sensitive chorda tympani nerve fibers was investigated in hamsters (Mesocricetus auratus). Without exception, hamsters increased consumption of aqueous solutions of nonsweet 0.1 M NaCl, 0.001 M quinine-HCl, 0.01 M citric acid, 0.001 M dithiothreitol, 0.01 M pyridine, 0.01 M 2-phenylethanol, 0.005 M i-amyl acetate, 0.01 M vanillin, half-saturated 1-menthol and 0.033 mM capsaicin if they were made sweet by adding 0.5 M sucrose. Since sucrose activates chorda tympani S fibers, activity in these nerve fibers may be sufficient for increased preference. To determine if S-fiber activity is necessary for preference, equally preferred sweet stimuli were presented to the tongue while recording responses of single chorda tympani fibers. S fibers were clearly activated by 0.03 M sucrose, 0.001 M Na saccharin, 0.01 M D-phenylalanine, 0.1 M glycine, 0.005 M dulcin and 0.03 M Na 2-mercaptoethanesulfonate but not by 0.01 M Ca cyclamate and 0.003 M Na 3-nitrobenzenesulfonate. Ca cyclamate weakly activated H fibers and Na 3-nitrobenzenesulfonate weakly activated N fibers. Thus, S-fiber chorda tympani activity may be sufficient but not necessary for sweet preference, which may be influenced by activity in fibers of other taste nerves.
Rehnberg
B G
BG
Center for Neurological Sciences, University of Connecticut Health Center, Farmington 06030.
Hettinger
T P
TP
Frank
M E
ME
D000818:Animals; D002628:Chemoreceptor Cells / Q000502:physiology*; D002814:Chorda Tympani Nerve / Q000502:physiology*; D006224:Cricetinae; D008297:Male; D008647:Mesocricetus; D012684:Sensory Thresholds / Q000502:physiology; D013395:Sucrose / Q000008:administration & dosage*; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000502:physiology; D014059:Tongue / Q000294:innervation
D013395:Sucrose