Responses of the rat chorda tympani nerve to glutamate-sucrose mixtures.
Monosodium glutamate (MSG) has a multifaceted, unusual taste to humans. Rats and other rodents also detect a complex taste to MSG. Responses of the chorda tympani nerve (CT) to glutamate applied to the front of the tongue were recorded in 13 anesthetized rats. Whole-nerve responses to 30 mM, 100 mM and 300 mM MSG mixed with 300 mM sucrose were recorded before and after adding 30 micro M amiloride to the rinse and stimulus solutions. Responses of CT single fibers were also recorded. Predictions from models of whole-nerve responses to binary mixtures were compared to the observed data. Results indicated that MSG-elicited CT responses have multiple sources, even in an amiloride-inhibited environment in rats. Those sources include responses of sucrose-sensitive CT neural units, which may provide the substrate for a sucrose-glutamate perceptual similarity, and responses of sucrose-insensitive CT neural units, which may respond synergistically to MSG-sucrose mixtures.
Formaker
B K
BK
Department of Oral Diagnosis, Division of Neurosciences, MC-1718, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA. Brad@neuron.uchc.edu
Stapleton
J R
JR
Roper
S D
SD
Frank
M E
ME
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002814:Chorda Tympani Nerve / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004594:Electrophysiology; D005503:Food Additives / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012970:Sodium Glutamate / Q000008:administration & dosage / Q000494:pharmacology*; D013395:Sucrose / Q000008:administration & dosage / Q000494:pharmacology*; D013549:Sweetening Agents / Q000008:administration & dosage / Q000494:pharmacology*; D013649:Taste; D013650:Taste Buds / Q000187:drug effects / Q000502:physiology
D005503:Food Additives; D013549:Sweetening Agents; D013395:Sucrose; D000584:Amiloride; D012970:Sodium Glutamate