title: N-methyl-D-aspartate receptors in the ventral tegmental area mediate the excitatory influence of Pavlovian stimuli on instrumental performance.
abstract: Pavlovian stimuli predictive of food can markedly amplify instrumental responding for food. This effect is termed Pavlovian-instrumental transfer (PIT). The ventral tegmental area (VTA) plays a key role in mediating PIT, however, it is yet unknown whether N-methyl-D-aspartate (NMDA)-type glutamate receptors in the VTA are involved in PIT. Here, we examined the effects of an NMDA-receptor blockade in the VTA on PIT. Immediately prior to PIT testing, rats were subjected to intra-VTA infusions of vehicle or of the NMDA-receptor antagonist 2-amino-5-phosphonopentanoic acid (AP-5) (1, 5 µg/side). In rats that received AP-5 at the lower dose, the PIT effect was intact, i.e. presentation of the Pavlovian stimulus enhanced instrumental responding. By contrast, in rats that received AP-5 at the higher dose, the PIT effect was blocked. The data suggest that NMDA receptors in the VTA mediate the activating effects of Pavlovian stimuli on instrumental responding.
authors.affiliation: Department Animal Physiology, University of Stuttgart, Pfaffenwaldring 57, 70550, Stuttgart, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Sommer
authors.affiliation: Department Animal Physiology, University of Stuttgart, Pfaffenwaldring 57, 70550, Stuttgart, Germany. hauber@bio.uni-stuttgart.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hauber
mesh_terms: D015763:2-Amino-5-phosphonovalerate / Q000008:administration & dosage; D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage; D008297:Male; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology*; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000502:physiology*
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D015763:2-Amino-5-phosphonovalerate
keywords: Instrumental conditioning; Pavlovian conditioning; Pavlovian–instrumental transfer; Rat; Ventral tegmental area