Orexin/hypocretin in the paraventricular nucleus of the thalamus mediates cocaine-seeking behavior in rats

2015 ◽  
Vol 146 ◽  
pp. e198
Author(s):  
Alessandra Matzeu ◽  
Tony M. Kerr ◽  
Friedbert Weiss ◽  
Remi Martin-Fardon
Keyword(s):  
Paraventricular Nucleus ◽  
Cocaine Seeking ◽  
Seeking Behavior

scholarly journals Administration of orexin A in the posterior paraventricular nucleus of the thalamus promotes cocaine-seeking behavior and is associated with hypothalamic activation

2017 ◽  
Author(s):  
Alessandra Matzeu ◽  
Rémi Martin-Fardon
Keyword(s):  
Paraventricular Nucleus ◽  
Priming Effect ◽  
Cocaine Dependence ◽  
Activation Pattern ◽  
Neuronal Activation ◽  
Drug Seeking ◽  
Protracted Abstinence ◽  
Cocaine Seeking ◽  
Seeking Behavior ◽  
History Of

ABSTRACTHypothalamic orexin (Orx) neurons that project to the paraventricular nucleus of the thalamus (PVT) have received growing interest because of their role in drug-seeking behavior. When injected in the posterior PVT (pPVT), OrxA reinstated extinguished cocaine-seeking behavior in rats that had long access (LgA) to cocaine for 6 h/day after an intermediate period of abstinence (I-Abst, 2-3 weeks). Considering the long-lasting nature of drug-seeking behavior and that the PVT sends projections to the hypothalamus, the present study examined whether (i) OrxA’s priming effect is preserved after a period of protracted abstinence (P-Abst, 4-5 weeks) in LgA rats and (ii) the neural activation pattern (i.e., Fos+ and Fos+/Orx+ cells) in the lateral hypothalamus (LH), dorsomedial hypothalamus (DMH), and perifornical area (PFA) following intra-pPVT OrxA administration that may explain OrxA-induced reinstatement in LgA animals. As reported previously, OrxA administration in the pPVT triggered cocaine-seeking behavior after I-Abst. With P-Abst, the priming effect of OrxA was absent. An intra-pPVT injection of OrxA produced a strong increase in neuronal activation (i.e., Fos expression) in the LH/DMH/PFA at I-Abst but not at P-Abst. The analysis of the activation (Fos+) of Orx neurons (Orx+) revealed an increase in Fos+/Orx+ expression in the LH/DMH/PFA at I-Abst only, thus paralleling the behavioral data. These data indicate that shortly after abstinence, PVT↔LH/DMH/PFA connections are strongly recruited in animals with a history of cocaine dependence. The lack of effect at P-Abst suggests that the function of Orx receptors and connectivity of the PVT↔LH/DMH/PFA circuit undergo significant neuroadaptations following P-Abst.SIGNIFICANCE STATEMENTA better understanding of the pathophysiological changes associated with cocaine addiction is needed to develop efficient pharmacotherapies. The paraventricular nucleus of the thalamus (PVT) and orexin (Orx) transmission within the PVT have been implicated in maladaptive (compulsive) behavior that is characteristic of drug addiction. The present study shows OrxA injections in the posterior PVT reinstates cocaine-seeking behavior in animals with a history of cocaine dependence, and this effect disappears after protracted abstinence, paralleled by the neuronal activation pattern in the hypothalamus. In subjects with a history of cocaine dependence, the function of Orx receptors and connectivity of the PVT↔ LH/DMH/PFA circuit undergo significant neuroadaptations.

scholarly journals Dynorphin counteracts orexin in the paraventricular nucleus of the thalamus: cellular and behavioral evidence

2017 ◽  
Author(s):  
Alessandra Matzeu ◽  
Marsida Kallupi ◽  
Olivier George ◽  
Paul Schweitzer ◽  
Rémi Martin-Fardon
Keyword(s):  
Paraventricular Nucleus ◽  
Glutamate Release ◽  
Critical Role ◽  
Brain Slices ◽  
Self Administration ◽  
Excitatory Transmission ◽  
Cocaine Seeking ◽  
Seeking Behavior ◽  
Male Wistar Rats ◽  
Behavioral Evidence

ABSTRACTThe orexin (Orx) system is known to play a critical role in drug addiction and reward-related behaviors. The dynorphin (Dyn) system, conversely, promotes depressive-like behavior and plays a key role in the aversive effects of stress. Orexin and Dyn are co-released and have opposing functions in reward and motivation in the ventral tegmental area (VTA). Earlier studies showed that microinjections of OrxA in the posterior paraventricular nucleus of the thalamus (pPVT) exerted priming-like effects and reinstated cocaine-seeking behavior, suggesting that Orx transmission in the pPVT participates in cocaine-seeking behavior. The present study sought to determine whether Orx and Dyn interact in the pPVT. Using a cellular approach, brain slices were prepared for whole-cell recordings and to study excitatory transmission in pPVT neurons. The superfusion of OrxA increased spontaneous glutamatergic transmission by increasing glutamate release onto pPVT neurons, whereas DynA decreased glutamate release. Furthermore, the augmentation of OrxA-induced glutamate release was reversed by DynA. To corroborate the electrophysiological data, separate groups of male Wistar rats were trained to self-administer cocaine or sweetened condensed milk (SCM). After self-administration training, the rats underwent extinction training and were tested with intra-pPVT administration of OrxA±DynA under extinction conditions. OrxA reinstated cocaine-and SCM-seeking behavior, with a greater effect in cocaine animals. DynA selectively blocked OrxA-induced cocaine seeking vs. SCM seeking. The data indicate that DynA in the pPVT prevents OrxA-induced cocaine seeking, perhaps by reversing the OrxA-induced increase in glutamate release, identifying a novel therapeutic target to prevent cocaine relapse.

scholarly journals Cocaine-Seeking Behavior Induced by Orexin A Administration in the Posterior Paraventricular Nucleus of the Thalamus Is Not Long-Lasting: Neuroadaptation of the Orexin System During Cocaine Abstinence

2021 ◽  
Vol 15 ◽  
Author(s):  
Alessandra Matzeu ◽  
Rémi Martin-Fardon
Keyword(s):  
Paraventricular Nucleus ◽  
Priming Effect ◽  
Cocaine Dependence ◽  
Orexin A ◽  
Drug Seeking ◽  
Intermediate Period ◽  
Protracted Abstinence ◽  
Cocaine Seeking ◽  
Seeking Behavior ◽  
Long Access

Hypothalamic orexin (Orx) projections to the paraventricular nucleus of the thalamus (PVT) have received growing interest because of their role in drug-seeking behavior. Using an established model of cocaine dependence (i.e., long access [LgA] to cocaine), we previously showed that OrxA injections in the posterior PVT (pPVT) reinstated extinguished cocaine-seeking behavior in rats after an intermediate period of abstinence (2–3 weeks). Considering the long-lasting nature of drug-seeking behavior, the present study examined whether the priming effect of intra-pPVT OrxA administration was preserved after a period of protracted abstinence (4–5 weeks) in rats that self-administered cocaine under LgA conditions. Furthermore, to better understand whether a history of cocaine dependence affects the Orx system—particularly the hypothalamic Orx↔pPVT connection—the number of Orx-expressing cells in the lateral hypothalamus (LH), dorsomedial hypothalamus (DMH), and perifornical area (PFA) and number of orexin receptor 1 (OrxR1)- and OrxR2-expressing cells in the pPVT were quantified. Orexin A administration in the pPVT induced cocaine-seeking behavior after intermediate abstinence, as reported previously. At protracted abstinence, however, the priming effect of OrxA was absent. A higher number of cells that expressed Orx was observed in the LH/DMH/PFA at both intermediate and protracted abstinence. In the pPVT, the number of OrxR2-expressing cells was significantly higher only at intermediate abstinence, with no changes in the number of OrxR1-expressing cells. These data build on our previous findings that the hypothalamic Orx↔pPVT connection is strongly recruited shortly after cocaine abstinence and demonstrate that the priming effect of OrxA is not long lasting. Furthermore, these findings suggest that throughout abstinence, the Orx↔pPVT connection undergoes neuroadaptive changes, reflected by alterations of the number of OrxR2-expressing cells in the pPVT.

Dopaminylation in Psychostimulant use Disorder Protects Against Psychostimulant Seeking Behavior by Normalizing Nucleus Accumbens (NAc) Dopamine Expression

2021 ◽  
Vol 09 ◽  
Author(s):  
Kenneth Blum ◽  
Mark S Gold ◽  
Jean L. Cadet ◽  
David Baron ◽  
Abdalla Bowirrat ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Histone H3 ◽  
D2 Receptor ◽  
Reward Processing ◽  
Allelic Polymorphism ◽  
Cocaine Withdrawal ◽  
Src Signaling ◽  
Chronic Cocaine ◽  
Cocaine Seeking ◽  
Seeking Behavior

Background: Repeated cocaine administration changes histone acetylation and methylation on Lys residues and Deoxyribonucleic acid (DNA) within the nucleus accumbens (NAc). Recently Nestler’s group explored histone Arg (R) methylation in reward processing models. Damez-Werno et al. (2016) reported that during investigator and selfadministration experiments, the histone mark protein-R-methyltransferase-6 (PRMT6) and asymmetric dimethylation of R2 on histone H3 (H3R2me2a) decreased in the rodent and cocaine-dependent human NAc. Overexpression of PRMT6 in D2-MSNs in all NAc neurons increased cocaine seeking, whereas PRMT6 overexpression in D1-MSNs protects against cocaine-seeking. Hypothesis: Hypothesizing that dopaminylation (H3R2me2a binding) occurs in psychostimulant use disorder (PSU), and the binding inhibitor Srcin1, like the major DRD2 A2 allelic polymorphism, protects against psychostimulant seeking behavior by normalizing nucleus accumbens (NAc) dopamine expression. Discussion: Numerous publications confirmed the association between the DRD2 Taq A1 allele (30-40 lower D2 receptor numbers) and severe cocaine dependence. Lepack et al. (2020) found that acute cocaine increases dopamine in NAc synapses, results in histone H3 glutamine 5 dopaminylation (H3Q5dop), and consequent inhibition of D2 expression. The inhibition increases with chronic cocaine use and accompanies cocaine withdrawal. They also found that the Src kinase sig-naling inhibitor 1 (Srcin1 or p140CAP) during cocaine withdrawal reduced H3R2me2a binding. Consequently, this inhibited dopaminylation induced a “homeostatic brake.” Conclusion: The decrease in Src signaling in NAc D2-MSNs, like the DRD2 Taq A2 allele, a well-known genetic mechanism protective against SUD normalized nucleus accumbens (NAc) dopamine expression and decreased cocaine reward and motivation to self-administer cocaine. The Srcin1 may be an important therapeutic target.

scholarly journals Stimulation of 5-HT1Breceptors enhances cocaine reinforcement yet reduces cocaine-seeking behavior

2009 ◽  
Vol 14 (4) ◽  
pp. 419-430 ◽  
Author(s):  
Nathan S. Pentkowski ◽  
Jazmin I. Acosta ◽  
Jenny R. Browning ◽  
Elizabeth C. Hamilton ◽  
Janet L. Neisewander
Keyword(s):  
Cocaine Seeking ◽  
Seeking Behavior ◽  
Stimulation Of
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