title: Differential role of insular cortex muscarinic and NMDA receptors in one-trial appetitive taste learning.
abstract: Our current understanding of the neurobiology of taste learning and memory has been greatly facilitated by the use of a reliable behavioural model, conditioned taste aversion (CTA). This model has revealed that the insular cortex (IC), specifically muscarinic and N-methyl-d-aspartate (NMDA) receptor activation in the IC, is critical for the formation of aversive taste memories. In contrast, current models of appetitive taste learning are less adequate, relying on the use of neophobic tastes (attenuation of neophobia) or on the integration of appetitive and aversive taste memories (latent inhibition of CTA). While these models have implicated IC muscarinic receptors, the involvement of NMDA receptors in the IC remains unclear. Here, we examined the role of both muscarinic and NMDA receptors in appetitive taste learning using a simple paradigm that is independent of neophobic and aversive components. First, we demonstrated that a single exposure to a novel taste, saccharin 0.1%, is sufficient to promote an appetitive taste memory as revealed by an increase in saccharin consumption during the second presentation. This increase was blocked by bilateral infusion in the IC of the muscarinic receptor antagonist, scopolamine. In contrast, infusion of the NMDA receptor antagonist, AP5, did not block appetitive taste learning but did abolish CTA. Therefore, common and distinct molecular substrates within the IC mediate appetitive versus aversive learning about the same taste.
authors.affiliation: INRA, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France; CNRS, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France; Université de Bordeaux, 33076 Bordeaux, France.
authors.forename: Shauna L
authors.initials: SL
authors.lastname: Parkes
authors.affiliation: Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 México DF, Mexico.
authors.forename: Vanesa
authors.initials: V
authors.lastname: De la Cruz
authors.affiliation: Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 México DF, Mexico.
authors.forename: Federico
authors.initials: F
authors.lastname: Bermúdez-Rattoni
authors.affiliation: CNRS, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, 33076 Bordeaux, France; Université de Bordeaux, 33076 Bordeaux, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Coutureau
authors.affiliation: INRA, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France; Université de Bordeaux, 33076 Bordeaux, France. Electronic address: guillaume.ferreira@bordeaux.inra.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D012439:Saccharin / Q000494:pharmacology; D012601:Scopolamine / Q000494:pharmacology; D013649:Taste / Q000502:physiology*; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D018691:Excitatory Amino Acid Antagonists; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D016194:Receptors, N-Methyl-D-Aspartate; C056639:2-amino-5-phosphopentanoic acid; D012601:Scopolamine; D012439:Saccharin; D014633:Valine
keywords: Appetitive; Insular cortex; Muscarinic receptor; NMDA receptor; Taste learning