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Involvement of AMPA receptor GluR2 subunits in stimulus reward learning: evidence from glutamate receptor gria 2 knockout mice.

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posted on 2023-06-07, 17:59 authored by Andy Mead, Dai Stephens
Presence of the glutamate receptor 2 (GluR2) subunit prevents calcium influx through AMPA-receptor complexes; deletion of this subunit results in enhanced hippocampal long-term potentiation. We investigated whether mice lacking the GluR2 subunit [gria2 knock-out (KO) mice] displayed impairments in learning stimulus-reward associations, and the subsequent ability of reward-paired cues to control motivated behavior. Both gria2 KO and wild-type (WT) mice learned to associate a light/tone stimulus with food delivery, as evidenced by approach toward the food magazine after the presentation of the cues (pavlovian conditioning). Subsequently, the cues also served to reinforce an operant response in both KO and WT mice (conditioned reinforcement), although response rates were greater in gria2 KOs. Responding for conditioned reinforcement was enhanced after 0.5 mg/kg amphetamine administration in WT mice, but not in KO mice. The ability of the cues to elicit approach behavior (conditioned approach) and to enhance responding for the reward (pavlovian-to-instrumental transfer; PIT) were also impaired in gria2 KO mice. This pattern of behavior resembles that seen after lesions of the central nucleus of the amygdala (CeA), an area rich in GluR2-containing AMPA receptors. Immunostaining revealed reduced GluR1 expression within both the basolateral amygdala and the CeA, suggesting that the behavioral deficits observed were unlikely to be caused by compensatory changes in GluR1. These results suggest that GluR2-containing AMPA receptors, possibly within the CeA, are critical for the formation of stimulus-reward associations necessary for PIT and conditioned approach, but are not involved in the plastic processes underlying the attribution of motivational value to the conditioned stimulus (CS).

History

Publication status

  • Published

File Version

  • Published version

Journal

Journal of Neuroscience

ISSN

1529-2401

Issue

29

Volume

23

Page range

9500-9507

Pages

8.0

Department affiliated with

  • Psychology Publications

Notes

Senior author

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

First Open Access (FOA) Date

2016-03-22

First Compliant Deposit (FCD) Date

2016-11-18

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