scholarly journals Synaptic Zn2+ potentiates the effects of cocaine on striatal dopamine neurotransmission and behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Juan L. Gomez ◽  
Jordi Bonaventura ◽  
Jacqueline Keighron ◽  
Kelsey M. Wright ◽  
Dondre L. Marable ◽  
...  

AbstractCocaine binds to the dopamine (DA) transporter (DAT) to regulate cocaine reward and seeking behavior. Zinc (Zn2+) also binds to the DAT, but the in vivo relevance of this interaction is unknown. We found that Zn2+ concentrations in postmortem brain (caudate) tissue from humans who died of cocaine overdose were significantly lower than in control subjects. Moreover, the level of striatal Zn2+ content in these subjects negatively correlated with plasma levels of benzoylecgonine, a cocaine metabolite indicative of recent use. In mice, repeated cocaine exposure increased synaptic Zn2+ concentrations in the caudate putamen (CPu) and nucleus accumbens (NAc). Cocaine-induced increases in Zn2+ were dependent on the Zn2+ transporter 3 (ZnT3), a neuronal Zn2+ transporter localized to synaptic vesicle membranes, as ZnT3 knockout (KO) mice were insensitive to cocaine-induced increases in striatal Zn2+. ZnT3 KO mice showed significantly lower electrically evoked DA release and greater DA clearance when exposed to cocaine compared to controls. ZnT3 KO mice also displayed significant reductions in cocaine locomotor sensitization, conditioned place preference (CPP), self-administration, and reinstatement compared to control mice and were insensitive to cocaine-induced increases in striatal DAT binding. Finally, dietary Zn2+ deficiency in mice resulted in decreased striatal Zn2+ content, cocaine locomotor sensitization, CPP, and striatal DAT binding. These results indicate that cocaine increases synaptic Zn2+ release and turnover/metabolism in the striatum, and that synaptically released Zn2+ potentiates the effects of cocaine on striatal DA neurotransmission and behavior and is required for cocaine-primed reinstatement. In sum, these findings reveal new insights into cocaine’s pharmacological mechanism of action and suggest that Zn2+ may serve as an environmentally derived regulator of DA neurotransmission, cocaine pharmacodynamics, and vulnerability to cocaine use disorders.

2020 ◽  
Author(s):  
Juan L. Gomez ◽  
Jordi Bonaventura ◽  
Jacqueline Keighron ◽  
Kelsey M. Wright ◽  
Dondre L. Marable ◽  
...  

AbstractCocaine binds to the dopamine transporter (DAT) in the striatum to regulate cocaine reward and seeking behavior. Zinc (Zn2+) also binds to the DAT, but the in vivo relevance of this interaction is unknown. We found that cocaine abuse in humans correlated with low postmortem striatal Zn2+ content. In mice, cocaine decreased striatal vesicular Zn2+ and increased striatal synaptic Zn2+ concentrations and Zn2+ uptake. Striatal synaptic Zn2+ increased cocaine’s in vivo potency at the DAT and was required for cocaine-induced DAT upregulation. Finally, genetic or dietary Zn2+ manipulations modulated cocaine locomotor sensitization, conditioned place preference, self-administration, and reinstatement. These findings reveal new insights into cocaine’s pharmacological mechanism of action and indicate that Zn2+ can serve as a critical environmentally derived regulator of human cocaine addiction.


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.


2018 ◽  
Author(s):  
Torry S. Dennis ◽  
Thomas C. Jhou ◽  
Jacqueline F. McGinty

ABSTRACTCocaine self-administration causes dephosphorylation of proteins in prelimbic (PL) cortex that mediate excitation-transcription coupling, suggesting that cocaine causes decreased activity in PL neurons. Thus, we used in vivo single-unit extracellular recordings in awake, behaving rats to measure activity in PL neurons before, during, and after cocaine self-administration on the first and last session day (range 12-14 days). On the last day, cocaine suppressed 52% of recorded neurons in the PL cortex when compared to a 20 min baseline, significantly more than the 23% of neurons suppressed on the first day of cocaine. There was no change in the percentage of neurons that were excited on the first vs. the last day of self-administration (14% vs. 13%, respectively). To determine whether the tonic inhibitory shift was induced by the behavior or by the drug itself, rats received a final session in which cocaine availability was delayed for the first 30 min or in which cocaine was administered non-contingently in the absence of levers or cues in a subset of rats. These manipulations indicated that cocaine was both necessary and sufficient to induce a downshift in PL neuronal activity. However, this activity decrease was not observed in rats that received only non-contingent cocaine for 12-14 days, indicating that contingency during self-administration training contributes to the cocaine-induced tonic downshift in PL activity. These data suggest that the session-by-session decrease in PL neuronal activity induced by cocaine is a reflection of learned drug-seeking behavior and, hence, reducing this inhibition may lessen cocaine addiction.


2020 ◽  
Author(s):  
Judit Cabana-Domínguez ◽  
Elena Martín-García ◽  
Ana Gallego-Roman ◽  
Rafael Maldonado ◽  
Noèlia Fernàndez-Castillo ◽  
...  

ABSTRACTBackground and PurposeCocaine addiction causes serious health problems and no effective treatment is available yet. We previously identified a genetic risk variant for cocaine addiction in the PLCB1 gene and found this gene upregulated in postmortem brains of cocaine abusers and in human dopaminergic neuron-like cells after an acute cocaine exposure. Here, we functionally tested the contribution of PLCB1 gene to cocaine addictive properties in mice.Experimental approachWe used heterozygous Plcb1 knockout mice (Plcb1+/-) and characterized their behavioral phenotype. Subsequently, mice were trained for operant conditioning and self-administered cocaine for 10 days. Plcb1+/- mice were assessed for cocaine motivation, followed by 26 days of extinction and finally evaluated for cue-induced reinstatement of cocaine seeking. Gene expression alterations after reinstatement were assessed in medial prefrontal cortex (mPFC) and hippocampus (HPC) by RNAseq.Key ResultsPlcb1+/- mice showed normal behavior, although they had increased anxiety and impaired short-term memory. Importantly, after cocaine self-administration and extinction, we found a reduction in the cue-induced reinstatement of cocaine-seeking behavior in Plcb1+/- mice. After reinstatement, we identified transcriptomic alterations in the medial prefrontal cortex of Plcb1+/- mice, mostly related to pathways relevant to addiction like the dopaminergic synapse and long-term potentiation.Conclusions and ImplicationsTo conclude, we found that heterozygous deletion of the Plcb1 gene decreases cue-induced reinstatement of cocaine seeking, pointing at PLCB1 as a possible therapeutic target for preventing relapse and treating cocaine addiction.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Spencer B. Huggett ◽  
Jeffrey S. Hatfield ◽  
Joshua D. Walters ◽  
John E. McGeary ◽  
Justine W. Welsh ◽  
...  

AbstractCocaine use presents a worldwide public health problem with high socioeconomic cost. No current pharmacologic treatments are available for cocaine use disorder (CUD) or cocaine toxicity. To explore pharmaceutical treatments for tthis disorder and its sequelae we analyzed gene expression data from post-mortem brain tissue of individuals with CUD who died from cocaine-related causes with matched cocaine-free controls (n = 71, Mage = 39.9, 100% male, 49% with CUD, 3 samples/brain regions). To match molecular signatures from brain pathology with potential therapeutics, we leveraged the L1000 database honing in on neuronal mRNA profiles of 825 repurposable compounds (e.g., FDA approved). We identified 16 compounds that were negatively associated with CUD gene expression patterns across all brain regions (padj < 0.05), all of which outperformed current targets undergoing clinical trials for CUD (all padj > 0.05). An additional 43 compounds were positively associated with CUD expression. We performed an in silico follow-up potential therapeutics using independent transcriptome-wide in vitro (neuronal cocaine exposure; n = 18) and in vivo (mouse cocaine self-administration; n = 12–15) datasets to prioritize candidates for experimental validation. Among these medications, ibrutinib was consistently linked with the molecular profiles of both neuronal cocaine exposure and mouse cocaine self-administration. We assessed the therapeutic efficacy of ibrutinib using the Drosophila melanogaster model. Ibrutinib reduced cocaine-induced startle response and cocaine-induced seizures (n = 61–142 per group; sex: 51% female), despite increasing cocaine consumption. Our results suggest that ibrutinib could be used for the treatment of cocaine use disorder.


2021 ◽  
Author(s):  
Spencer B. Huggett ◽  
Jeffrey S. Hatfield ◽  
Joshua D. Walters ◽  
John E. McGeary ◽  
Justine W. Welsh ◽  
...  

ABSTRACTCocaine use presents a worldwide public health problem with high socioeconomic cost. Current treatments for cocaine use disorder (CUD) are suboptimal and rely primarily on behavioral interventions. To explore pharmaceutical treatments for CUD, we analyzed genome-wide gene expression data from publically availble human brain tissues (midbrain, hippocampus and prefrontal cortex neurons) from 71 individuals (mean age = 39.9, 100% male, 36 with CUD and 35 matched controls). We leveraged the L1000 database to investigate molecular associations between neuronal mRNA profiles from 825 repurposable compounds (e.g., FDA approved) with human CUD gene expression in the brain. We identified 16 compounds that were negatively associated with CUD gene expression patterns across all brain regions (padj < 0.05), all of which outperformed current targets undergoing clinical trials for CUD (all padj > 0.05). We tested the effectiveness of these compounds using independent transcriptome-wide in vitro (neuronal cocaine exposure; n=18) and in vivo (mouse cocaine self-administration; prefrontal cortex, hippocampus and midbrain; n = 12-15) datasets. Among these medications, Ibrutinib demonstrated negative associations with both neuronal cocaine exposure and mouse cocaine self-administration. To obtain experimental confirmation of therapeutic effects of Ibrutinib on CUD, we used the Drosophila melanogaster model, which enables highthroughput quantification of behavioral responses in defined genetic backgrounds and controlled environmental conditions. Ibrutinib altered cocaine-induced changes in startle response and reduced the occurrence of cocaine-induced seizures (n = 61-142 per group; sex: 51%female). Our results identify Ibrutinib, an FDA approved medication, as a potential therapeutic for cocaine neurotoxicity.


2021 ◽  
Vol 15 ◽  
Author(s):  
Hadas Ahdoot-Levi ◽  
Ofri Croitoru ◽  
Tzofnat Bareli ◽  
Einav Sudai ◽  
Hilla Peér-Nissan ◽  
...  

Cocaine addiction is an acquired behavioral state developed in vulnerable individuals after cocaine exposure. It is characterized by compulsive drug-seeking and high vulnerability to relapse even after prolonged abstinence, associated with decreased neurogenesis in the hippocampus. This addictive state is hypothesized to be a form of “memory disease” in which the drug exploits the physiological neuroplasticity mechanisms that mediate regular learning and memory processes. Therefore, a major focus of the field has been to identify the cocaine-induced neuroadaptations occurring in the usurped brain’s reward circuit. The neurosteroid dehydroepiandrosterone (DHEA) affects brain cell morphology, differentiation, neurotransmission, and memory. It also reduces drug-seeking behavior in an animal model of cocaine self-administration. Here, we examined the long-lasting effects of DHEA treatment on the attenuation of cocaine-seeking behavior. We also examined its short- and long-term influence on hippocampal cells architecture (neurons and astrocytes). Using a behavioral examination, immunohistochemical staining, and diffusion tensor imaging, we found an immediate effect on tissue density and activation of astrocytes, which has a continuous beneficial effect on neurogenesis and tissue organization. This research emphasizes the requites concert between astrocytes and neurons in the rehabilitation from addiction behavior. Thus, DHEA may serve as a treatment that corrects brain damage following exposure to and abstinence from cocaine.


2018 ◽  
Author(s):  
Jiann W. Yeoh ◽  
Morgan H. James ◽  
Cameron D. Adams ◽  
Jaideep S. Bains ◽  
Takeshi Sakurai ◽  
...  

AbstractThe perifornical/lateral hypothalamic area (LHA) orexin (hypocretin) system is involved in drug-seeking behavior elicited by drug-associated stimuli. Cocaine exposure is associated with presynaptic plasticity at LHA orexin cells such that excitatory input to orexin cells is enhanced, both acutely and into withdrawal. These changes may augment orexin cell reactivity to drug-related cues during abstinence and contribute to relapse-like behavior. Studies in hypothalamic slices from drug-naïve animals indicate that agonism of group III metabotropic glutamate receptors (mGluRs) reduces presynaptic glutamate release onto orexin cells. Therefore, we examined the group III mGluR system as a potential target to reduce orexin cell excitability in-vivo, and tested whether activating these receptors could normalize orexin cell activity following cocaine and reduce cocaine-seeking elicited by drug-associated stimuli during abstinence. First, we verified that group III mGluRs regulate orexin cell activity in vivo by showing that intra-LHA infusions of the selective agonist L-(+)-2-Amino-4-phosphonobutyric acid (L-AP4) reduces Fos expression in orexin cells following 24h food deprivation. Next, we extended these findings to show that intra-LHA L-AP4 infusions reduced discriminative stimulus-driven cocaine-seeking following withdrawal. L-AP4 had no effect on general motor activity of sucrose self-administration. Finally, using whole-cell patch clamp recordings from identified orexin cells in orexin-GFP transgenic mice, we show that enhanced presynaptic drive to orexin cells persists for up to 14d into withdrawal and that this plasticity is normalized by L-AP4. L-AP4 had no effect on measures of postsynaptic plasticity in cocaine-exposed animals. Together, these data indicate that agonism of LHA group III mGluRs reduces orexin cell activity in-vivo and is an effective strategy to suppress cocaine-seeking behavior following withdrawal. These effects are likely mediated, at least in part, by normalization of presynaptic plasticity at orexin cells that occurs as a result of cocaine exposure.


2016 ◽  
Vol 55 (01) ◽  
pp. 21-28 ◽  
Author(s):  
C. Antke ◽  
H. Hautzel ◽  
H.-W. Mueller ◽  
S. Nikolaus

SummaryNumerous neurologic and psychiatric conditions are treated with pharmacological compounds, which lead to an increase of synaptic dopamine (DA) levels. One example is the DA precursor L-3,4-dihydroxyphenylalanine (L-DOPA), which is converted to DA in the presynaptic terminal. If the increase of DA concentrations in the synaptic cleft leads to competition with exogenous radioligands for presynaptic binding sites, this may have implications for DA transporter (DAT) imaging studies in patients under DAergic medication.This paper gives an overview on those findings, which, so far, have been obtained on DAT binding in human Parkinson’s disease after treatment with L-DOPA. Findings, moreover, are related to results obtained on rats, mice or non-human primates. Results indicate that DAT imaging may be reduced in the striata of healthy animals, in the unlesioned striata of animal models of unilateral Parkinson’s disease and in less severly impaired striata of Parkinsonian patients, if animal or human subjects are under acute or subchronic treatment with L-DOPA. If also striatal DAT binding is susceptible to alterations of synaptic DA levels, this may allow to quantify DA reuptake in analogy to DA release by assessing the competition between endogenous DA and the administered exogenous DAT radioligand.


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