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Drug-paired contextual stimuli increase dendritic spine dynamics in select nucleus accumbens neurons

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posted on 2023-06-09, 18:12 authored by Bryan SingerBryan Singer, Nancy Bubula, Dongdong Li, Magdalena M Przybycien-Szymanska, Vytautas P Bindokas, Paul Vezina
Repeated exposure to amphetamine leads to both associative conditioning and non-associative sensitization. Here we assessed the contribution of neuronal ensembles in the nucleus accumbens (NAcc) to these behaviors. Animals exposed to amphetamine IP or in the ventral tegmental area (VTA) showed a sensitized locomotor response when challenged with amphetamine weeks later. Both exposure routes also increased ?FosB levels in the NAcc. Further characterization of these ?FosB+ neurons, however, revealed that amphetamine had no effect on dendritic spine density or size, indicating that these neurons do not undergo changes in dendritic spine morphology that accompany the expression of non-associative sensitization. Additional experiments determined how neurons in the NAcc contribute to the expression of associative conditioning. A discrimination-learning procedure was used to expose rats to IP or VTA amphetamine either Paired or Unpaired with an open field. As expected, compared to Controls, Paired rats administered IP amphetamine subsequently showed a conditioned locomotor response when challenged with saline in the open field, an effect accompanied by an increase in c-Fos+ neurons in the medial NAcc. Further characterization of these c-Fos+ cells revealed that Paired rats showed an increase in the density of dendritic spines and the frequency of medium-sized spines in the NAcc. In contrast, Paired rats previously exposed to VTA amphetamine showed neither conditioned locomotion nor conditioned c-Fos+ expression. Together, these results suggest a role for c-Fos+ neurons in the medial NAcc and rapid changes in the morphology of their dendritic spines in the expression of conditioning evoked by amphetamine-paired contextual stimuli.

History

Publication status

  • Published

File Version

  • Accepted version

Journal

Neuropsychopharmacology

ISSN

0893-133X

Publisher

Springer Nature

Issue

8

Volume

41

Page range

2178-2187

Department affiliated with

  • Psychology Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2019-06-24

First Open Access (FOA) Date

2019-06-24

First Compliant Deposit (FCD) Date

2019-06-24

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