title: Linoleic acid increases chorda tympani nerve responses to and behavioral preferences for monosodium glutamate by male and female rats.
abstract: Previous studies suggest that the chorda tympani nerve (CT) is important in transmitting fat taste information to the central nervous system. However, the contribution of the CT in this process may depend upon the presence of other taste stimuli and/or differ in males and females. Accordingly, the present study investigated the role of the CT in free fatty acid taste processing by examining electrophysiological activity of the CT in response to the free fatty acid linoleic acid (LA), as well as by measuring behavioral responses to LA-taste mixtures. We recorded whole nerve responses from the CT in response to lingual application of LA with or without monosodium glutamate (MSG) in anesthetized male and female rats. In addition, we examined preferences for MSG + LA taste mixtures in behavioral tests. Although lingual application of LA alone did not produce CT whole nerve responses, coapplication of LA and MSG elicited greater CT responses than did MSG alone. These findings were paralleled by greater preferences for MSG + LA taste mixtures than for MSG alone. In both cases, the effect was particularly pronounced in male rats. Thus LA enhances CT activity and behavioral responses to LA + MSG taste mixtures, although there are sex differences in the effects. These results suggest that CT input is important in mediating behavioral responses to fat taste, but the effects depend upon other taste stimuli and differ in males and females.
authors.affiliation: Dept. of Psychology and Program in Neuroscience, The Florida State Univ., Tallahassee, FL 32306-1270, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Stratford
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Curtis
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Contreras
mesh_terms: D000758:Anesthesia; D000818:Animals; D002814:Chorda Tympani Nerve / Q000187:drug effects* / Q000502:physiology; D004041:Dietary Fats / Q000494:pharmacology; D004594:Electrophysiology; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology; D005260:Female; D005518:Food Preferences / Q000187:drug effects* / Q000502:physiology; D019787:Linoleic Acid / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics; D012970:Sodium Glutamate / Q000494:pharmacology*; D013649:Taste / Q000187:drug effects* / Q000502:physiology; D014059:Tongue / Q000294:innervation / Q000502:physiology
chemical_list: D004041:Dietary Fats; D019787:Linoleic Acid; D012970:Sodium Glutamate