Cocaine Paired Environment Increases SATB2 Levels in the Rat Paraventricular Thalamus.

Ahmad Salti,Cristina Lemos,Rana El Rawas,Galina Apostolova,Kai K Kummer,Georg Dechant

doi:10.3389/fnbeh.2018.00224

Ahmad Salti, Cristina Lemos + Show 4 more

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https://doi.org/10.3389/fnbeh.2018.00224

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Abstract

SATB2 is a DNA binding protein that specifically binds the nuclear matrix attachment region and functions as a regulator of the transcription of large chromatin domains. Unlike its well addressed role during brain development, the role of SATB2 in adult brain is under-investigated. It has been shown that deletion of SATB2 from the forebrain of adult mice significantly impaired long-term memory for contextual fear and object recognition memory. The aim of the present study was to investigate the effects of appetitive stimuli such as cocaine and social interaction (SI) on SATB2 expression in the adult rat brain. For that, we performed conditioned place preference (CPP) to cocaine (15 mg/kg) and to SI, then assessed SATB2 expression in the brain 1 h (24 h after the last conditioning) and 24 h (48 h after the last conditioning) after the CPP test. We found that SATB2 expression in the paraventricular thalamus of rats was increased 1 h after the cocaine CPP test. This increase was selective for the cocaine-paired environment since the SI-paired environment did not increase SATB2 expression in the paraventricular thalamus. Also, the cocaine paired environment-induced increase of SATB2 levels in the paraventricular thalamus was due to cocaine conditioning as the unpaired cocaine group did not show an increase of SATB2 in the paraventricular thalamus. These results suggest that SATB2 in the paraventricular thalamus appears to be involved in the association between cocaine effects and environmental context. Further studies are needed to address the functional role of SATB2 in cocaine conditioning.

Highlights

Reward-related memories play a crucial role in drug dependence (Hyman et al, 2006)
SATB2 was found to be expressed in the prefrontal cortex subregions (Cingulate cortex area- Cingulate cortex area 1 (Cg1), InfralimbicIL and Prelimbic cortex- PrL), field CA1 of the hippocampus, paraventricular thalamic nucleus (PV), arcuate hypothalamic nucleus (Arc), ventromedial hypothalamus (VM), basomedial amygdaloid nucleus (BMA) and posterolateral cortical amygdaloid nucleus (Plco) of rats (Supplementary Figure S1)
We showed that the environment paired with cocaine increased SATB2 levels in the paraventricular thalamus and that this increase was selective for the group conditioned with cocaine, as Social interaction (SI) conditioned place preference (CPP) did not induce an increase in SATB2 levels in the paraventricular thalamus

Summary

Introduction

Conditioned place preference (CPP) is one of the experimental protocols that provides information about the rewarding effects of the contextual cues associated with a stimulus (Bardo and Bevins, 2000). In CPP, the subject is paired with drug reward in a specific context during several sessions. Subjects still prefer the cocaine associated context long after pairing sessions occurred (Fritz et al, 2011). Social interaction (SI) is a natural reward shown to induce place preference (Kummer et al, 2011; El Rawas and Saria, 2015) and to be a beneficial alternative to cocaine (Fritz et al, 2011). SI reward was reported to have the same reward value as cocaine in rats (Fritz et al, 2011) and to activate almost the same brain regions of the reward circuitry (El Rawas et al, 2012)

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