Alternation in dopamine D2-like and metabotropic glutamate type 5 receptor density caused by differing housing conditions during abstinence from cocaine self-administration in rats

2019 ◽  
Vol 33 (3) ◽  
pp. 372-382 ◽  
Author(s):  
Małgorzata Frankowska ◽  
Joanna Miszkiel ◽  
Lucyna Pomierny-Chamioło ◽  
Bartosz Pomierny ◽  
Giuseppe Giannotti ◽  
...  

Background: Environmental conditions have an important function in substance use disorder, increasing or decreasing the risks of relapse. Several studies strongly support the role of the dopamine D2-like and metabotropic glutamate type 5 receptors in maladaptive neurobiological responses to cocaine reward and relapse. Aims: The present study employed cocaine self-administration with yoked-triad procedure in rats to explore whether drug abstinence in different housing conditions affects the drug-seeking behaviour and the dopamine D2-like and metabotropic glutamate type 5 receptor density and affinity in several regions of the animal brain. Methods: Rats were trained to self-administer cocaine and later they were forced to abstain either in: (a) enriched environment or (b) isolation cage conditions to evaluate the effect of housing conditions on the drug-seeking behaviour and to assess changes concerning receptors in animals brain. Results: Our results show that exposure to enriched environment conditions strongly reduced active lever presses during cue-induced drug-seeking. At the neurochemical level, we demonstrated a significant increase in the dopamine D2-like receptor density in the prefrontal cortex in animals following drug abstinence in isolation cage or enriched environment conditions, and the reduction in their density in the dorsal striatum provoked by isolation cage conditions. The metabotropic glutamate type 5 receptor density decreased only in the prefrontal cortex after isolation cage and enriched environment abstinence. Conclusions: This study shows the different impacts caused by the type of housing conditions during abstinence from cocaine self-administration on drug-seeking behaviour in rats. The observed changes in the dopamine D2-like and metabotropic glutamate type 5 receptor Bmax and/or Kd values were brain-region specific and related to either pharmacological and/or motivational features of cocaine.

2018 ◽  
Vol 56 (5) ◽  
pp. 3603-3615 ◽  
Author(s):  
Christopher A. Blackwood ◽  
Reece Hoerle ◽  
Michael Leary ◽  
Jennifer Schroeder ◽  
Martin O. Job ◽  
...  

2008 ◽  
Vol 363 (1507) ◽  
pp. 3233-3243 ◽  
Author(s):  
Hans S Crombag ◽  
Jennifer M Bossert ◽  
Eisuke Koya ◽  
Yavin Shaham

In humans, exposure to environmental contexts previously associated with drug intake often provokes relapse to drug use, but the mechanisms mediating this relapse are unknown. Based on early studies by Bouton & Bolles on context-induced ‘renewal’ of learned behaviours, we developed a procedure to study context-induced relapse to drug seeking. In this procedure, rats are first trained to self-administer drug in one context. Next, drug-reinforced lever responding is extinguished in a different (non-drug) context. Subsequently, context-induced reinstatement of drug seeking is assessed by re-exposing rats to the drug-associated context. Using variations of this procedure, we and others reported reliable context-induced reinstatement in rats with a history of heroin, cocaine, heroin–cocaine combination, alcohol and nicotine self-administration. Here, we first discuss potential psychological mechanisms of context-induced reinstatement, including excitatory and inhibitory Pavlovian conditioning, and occasion setting. We then summarize results from pharmacological and neuroanatomical studies on the role of several neurotransmitter systems (dopamine, glutamate, serotonin and opioids) and brain areas (ventral tegmental area, accumbens shell, dorsal striatum, basolateral amygdala, prefrontal cortex, dorsal hippocampus and lateral hypothalamus) in context-induced reinstatement. We conclude by discussing the clinical implications of rat studies on context-induced reinstatement of drug seeking.


2019 ◽  
Author(s):  
William C. Buchta ◽  
Aubin Moutal ◽  
Bethany Hines ◽  
Constanza Garcia-Keller ◽  
Alexander C.W. Smith ◽  
...  

AbstractCocaine addiction is a major health concern with limited effective treatment options. A better understanding of mechanisms underlying relapse may help inform the development of new pharmacotherapies. Emerging evidence suggests that collapsin response mediator protein 2 (CRMP2) regulates presynaptic excitatory neurotransmission and contributes to pathological changes during diseases, such as neuropathic pain and substance use disorders. We examined the role of CRMP2 and its interactions with a known binding partner, CaV2.2, in cocaine-seeking behavior. We employed the rodent self-administration model of relapse to drug-seeking and focused on the prefrontal cortex (PFC) for its well-established role in reinstatement behaviors. Our results indicated that repeated cocaine self-administration resulted in a dynamic and persistent alteration in the PFC expression of CRMP2 and its binding partner, the CaV2.2 (N-type) voltage-gated calcium channel. Following cocaine self-administration and extinction training, the expression of both CRMP2 and CaV2.2 was reduced relative to Yoked saline controls. By contrast, cued-reinstatement potentiated CRMP2 expression and increased CaV2.2 expression above extinction levels. Lastly, we utilized the recently developed peptide myr-TAT-CBD3 to disrupt the interaction between CRMP2 and CaV2.2 in vivo. We assessed the reinstatement behavior after infusing this peptide directly into the medial PFC and found that it decreased cue-induced reinstatement of cocaine seeking. Taken together, these data suggest that neuroadaptations in the CRMP2/CaV2.2 signaling cascade in the PFC can facilitate drug seeking behavior. Targeting such interactions has implications for the treatment of cocaine relapse behavior.


2021 ◽  
Author(s):  
◽  
Ross van de Wetering

<p>Rationale. ±3,4-Methylenedioxymethamphetamine (MDMA; ‘ecstasy’) is a popular recreational drug of abuse. Like other drugs of abuse, a proportion of users develop symptoms that are characteristic of a Substance Use Disorder (SUD). The behavioural and neurobiological consequences of repeated misuse of MDMA are not well understood, however.  Objectives. The purpose of the present thesis was to investigate behaviourally relevant neuroadaptations that develop with repeated MDMA exposure in laboratory rats.  Methods. First, the effect of chronic, long-access (6 hour) self-administration of MDMA on the accumulation of the transcription factor, ΔFosB, in the nucleus accumbens (core, shell), dorsal striatum (dorsomedial, dorsolateral, ventromedial, ventrolateral), prefrontal cortex (anterior cingulate, prelimbic, infralimbic, orbitofrontal), amygdala (central, basolateral), ventral tegmental area (anterior, posterior), and raphe (dorsal, median) was measured using immunohistochemistry. Second, the behavioural relevance of these findings was determined by examining the effect of bi-lateral intra-striatal (nucleus accumbens, dorsomedial striatum, dorsolateral striatum) microinjections of MDMA (200 μg/1 μL/side) on the expression of behavioural sensitisation following two days of withdrawal from a regimen of repeated, systemic MDMA exposure (10 mg/kg/day, i.p., for 5 days). Third, a procedure was developed to examine neurochemical correlates of sensitised MDMA-produced behaviour (0, 5, 10 mg/kg, i.p.) following the same regimen of repeated MDMA exposure. Samples were collected from the medial striatum using in vivo microdialysis and the extracellular concentrations of serotonin, dopamine, MDMA, and their metabolites were quantified using liquid chromatography coupled with quadrupole time-of-flight (Q-TOF) mass spectrometry. Lastly, a unique untargeted metabolomics procedure was developed to further analyse these microdialysis samples and to identify novel or unexpected metabolites that were relevant to the sensitised behavioural response produced by MDMA.  Results. MDMA self-administration produced region-dependant increases in ΔFosB. Significant increases in ΔFosB were observed in the nucleus accumbens core, the medial areas of the dorsal striatum, as well as all areas of the prefrontal cortex and amygdala. Small, but significant increases were also observed in the dorsal raphe. Increases were observed in the nucleus accumbens shell and the posterior tail of the ventral tegmental area, but these increases were not significant following statistical correction for multiple comparisons. Acute exposure to MDMA increased locomotor activity only when the drug was infused into the nucleus accumbens. Following repeated systemic exposure, behavioural sensitisation was expressed when MDMA was infused into both the nucleus accumbens or the dorsomedial striatum, but not the dorsolateral striatum. Analysis of microdialysates from the medial striatum indicated that behavioural sensitisation was accompanied by small increases in baseline levels of extracellular serotonin and decreased MDMA-produced increases in serotonin, but these changes were not statistically significant. Behavioural sensitisation was also accompanied by increased extracellular concentrations of dopamine at baseline and following acute MDMA exposure, but these data were not statistically analysed due to small sample sizes. MDMA-produced extracellular concentrations of MDMA did not change with repeated exposure. Untargeted metabolomics revealed potential changes in MDMA and dopamine metabolism that might be relevant to the sensitised behavioural response.  Conclusions. The findings of the current research suggest that repeated MDMA exposure results in many of the same neuroadaptations that result from repeated exposure to other drugs of abuse. These included increased ΔFosB expression in many brain regions that are relevant to addiction, such as the nucleus accumbens, dorsal striatum, and prefrontal cortex. Dopaminergic mechanisms also appeared to be influenced and were associated with sensitised MDMA-produced behaviour. Surprisingly, serotonergic mechanisms were not significantly impacted by repeated MDMA exposure under the current conditions. Some of the procedures developed in this thesis are unique and may be of value for future research investigating the neurochemical underpinnings of addictive behaviour or other disease states.</p>


2021 ◽  
Author(s):  
◽  
Ross van de Wetering

<p>Rationale. ±3,4-Methylenedioxymethamphetamine (MDMA; ‘ecstasy’) is a popular recreational drug of abuse. Like other drugs of abuse, a proportion of users develop symptoms that are characteristic of a Substance Use Disorder (SUD). The behavioural and neurobiological consequences of repeated misuse of MDMA are not well understood, however.  Objectives. The purpose of the present thesis was to investigate behaviourally relevant neuroadaptations that develop with repeated MDMA exposure in laboratory rats.  Methods. First, the effect of chronic, long-access (6 hour) self-administration of MDMA on the accumulation of the transcription factor, ΔFosB, in the nucleus accumbens (core, shell), dorsal striatum (dorsomedial, dorsolateral, ventromedial, ventrolateral), prefrontal cortex (anterior cingulate, prelimbic, infralimbic, orbitofrontal), amygdala (central, basolateral), ventral tegmental area (anterior, posterior), and raphe (dorsal, median) was measured using immunohistochemistry. Second, the behavioural relevance of these findings was determined by examining the effect of bi-lateral intra-striatal (nucleus accumbens, dorsomedial striatum, dorsolateral striatum) microinjections of MDMA (200 μg/1 μL/side) on the expression of behavioural sensitisation following two days of withdrawal from a regimen of repeated, systemic MDMA exposure (10 mg/kg/day, i.p., for 5 days). Third, a procedure was developed to examine neurochemical correlates of sensitised MDMA-produced behaviour (0, 5, 10 mg/kg, i.p.) following the same regimen of repeated MDMA exposure. Samples were collected from the medial striatum using in vivo microdialysis and the extracellular concentrations of serotonin, dopamine, MDMA, and their metabolites were quantified using liquid chromatography coupled with quadrupole time-of-flight (Q-TOF) mass spectrometry. Lastly, a unique untargeted metabolomics procedure was developed to further analyse these microdialysis samples and to identify novel or unexpected metabolites that were relevant to the sensitised behavioural response produced by MDMA.  Results. MDMA self-administration produced region-dependant increases in ΔFosB. Significant increases in ΔFosB were observed in the nucleus accumbens core, the medial areas of the dorsal striatum, as well as all areas of the prefrontal cortex and amygdala. Small, but significant increases were also observed in the dorsal raphe. Increases were observed in the nucleus accumbens shell and the posterior tail of the ventral tegmental area, but these increases were not significant following statistical correction for multiple comparisons. Acute exposure to MDMA increased locomotor activity only when the drug was infused into the nucleus accumbens. Following repeated systemic exposure, behavioural sensitisation was expressed when MDMA was infused into both the nucleus accumbens or the dorsomedial striatum, but not the dorsolateral striatum. Analysis of microdialysates from the medial striatum indicated that behavioural sensitisation was accompanied by small increases in baseline levels of extracellular serotonin and decreased MDMA-produced increases in serotonin, but these changes were not statistically significant. Behavioural sensitisation was also accompanied by increased extracellular concentrations of dopamine at baseline and following acute MDMA exposure, but these data were not statistically analysed due to small sample sizes. MDMA-produced extracellular concentrations of MDMA did not change with repeated exposure. Untargeted metabolomics revealed potential changes in MDMA and dopamine metabolism that might be relevant to the sensitised behavioural response.  Conclusions. The findings of the current research suggest that repeated MDMA exposure results in many of the same neuroadaptations that result from repeated exposure to other drugs of abuse. These included increased ΔFosB expression in many brain regions that are relevant to addiction, such as the nucleus accumbens, dorsal striatum, and prefrontal cortex. Dopaminergic mechanisms also appeared to be influenced and were associated with sensitised MDMA-produced behaviour. Surprisingly, serotonergic mechanisms were not significantly impacted by repeated MDMA exposure under the current conditions. Some of the procedures developed in this thesis are unique and may be of value for future research investigating the neurochemical underpinnings of addictive behaviour or other disease states.</p>


2020 ◽  
Author(s):  
Matthew J. Muelbl ◽  
Breanna Glaeser ◽  
Alok S. Shah ◽  
Rachel Chiariello ◽  
Natalie N. Nawarawong ◽  
...  

AbstractTraumatic brain injury (TBI) and drug addiction are common comorbidities, but it is unknown if the neurological sequelae of TBI contribute to this relationship. We have previously reported elevated oxycodone seeking after drug self-administration in rats that received repeated blast TBI (rbTBI). TBI and exposure to drugs of abuse can each change structural and functional neuroimaging outcomes, but it is unknown if there are interactive effects of injury and drug exposure. To determine the effects of TBI and oxycodone exposure, we subjected rats to rbTBI and oxycodone self-administration and measured drug seeking and several neuroimaging measures. We found interactive effects of rbTBI and oxycodone on fractional anisotropy (FA) in the nucleus accumbens (NAc), and that FA in the medial prefrontal cortex (mPFC) was correlated with drug seeking. We also found an interactive effect of injury and drug on widespread functional connectivity and regional homogeneity of the BOLD response, and that interhemispheric functional connectivity in the infralimbic medial prefrontal cortex positively correlated with drug seeking. In conclusion, rbTBI and oxycodone self-administration had interactive effects on structural and functional MRI measures, and correlational effects were found between some of these measures and drug seeking. These data support the hypothesis that TBI and opioid exposure produce neuroadaptations that contribute to addiction liability.


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