The oxytocin analogue carbetocin prevents priming-induced reinstatement of morphine-seeking: Involvement of dopaminergic, noradrenergic and MOPr systems.

Relapse to illicit drug-seeking following abstinence is a major challenge for the treatment of addiction as no effective pharmacotherapy is available. We have recently shown that activating the central oxytocinergic system prevents emotional impairment and stress-induced reinstatement associated with opioid withdrawal. Here, we investigated whether the oxytocin analogue carbetocin (CBT) is able to reverse morphine-primed reinstatement of conditioned-place preference (CPP) in mice. The mechanism underlining the behavioural effect of CBT was investigated by assessing the involvement of the striatal noradrenergic and dopaminergic systems in CBT reversal of priming- and stress-induced reinstatement of opioid CPP. In addition, given recent evidence suggesting the presence of oxytocin receptor (OTR)-μ-opioid receptor (MOPr) interactions in the brain, we further explored these interactions by carrying out OTR autoradiographic binding in brain of mice lacking MOPr. CBT administration prevented priming-induced reinstatement of morphine CPP. While an acute effect of CBT in enhancing dopamine turnover was observed following stress- and priming-induced reinstatement, CBT significantly decreased striatal noradrenaline turnover only following priming-induced reinstatement. Moreover, a significant brain region- specific increase in OTR binding was observed in MOPr knockout mice, indicating the presence of a possible OTR-MOPr interaction, which may be involved in the modulation of relapse. These results support the oxytocinergic system as a promising target for the prevention of relapse to opioid use and highlight the differential involvement of monoaminergic systems on the effects of OTR stimulation in preventing stress- and priming-induced reinstatement of opioid CPP behaviour

Methamphetamine withdrawal induces activation of CRF neurons in the brain stress system in parallel with an increased activity of cardiac sympathetic pathways.

Methamphetamine (METH) addiction is a major public health problem in some countries. There is evidence to suggest that METH use is associated with increased risk of developing cardiovascular problems. Here, we investigated the effects of chronic METH administration and withdrawal on the activation of the brain stress system and cardiac sympathetic pathways. Mice were treated with METH (2 mg/kg, i.p.) for 10 days and left to spontaneous withdraw for 7 days. The number of corticotrophin-releasing factor (CRF), c-Fos, and CRF/c-Fos neurons was measured by immunohistochemistry in the paraventricular nucleus of the hypothalamus (PVN) and the oval region of the bed nucleus of stria terminalis (ovBNST), two regions associated with cardiac sympathetic control. In parallel, levels of catechol-o-methyl-transferase (COMT), tyrosine hydroxylase (TH), and heat shock protein 27 (Hsp27) were measured in the heart. In the brain, chronic-METH treatment enhanced the number of c-Fos neurons and the CRF neurons with c-Fos signal (CRF+/c-Fos+) in PVN and ovBNST. METH withdrawal increased the number of CRF+neurons. In the heart, METH administration induced an increase in soluble (S)-COMT and membrane-bound (MB)-COMT without changes in phospho (p)-TH, Hsp27, or pHsp27. Similarly, METH withdrawal increased the expression of S- and MB-COMT. In contrast to chronic treatment, METH withdrawal enhanced levels of (p)TH and (p)Hsp27 in the heart. Overall, our results demonstrate that chronic METH administration and withdrawal activate the brain CRF systems associated with the heart sympathetic control and point towards a METH withdrawal induced activation of sympathetic pathways in the heart. Our findings provide further insight in the mechanism underlining the cardiovascular risk associated with METH use and proposes targets for its treatment

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Maternal Separation Impairs Cocaine-Induced Behavioural Sensitization in Adolescent Mice

Adverse early-life conditions induce persistent disturbances that give rise to negative emotional states. Therefore, early life stress confers increased vulnerability to substance use disorders, mainly during adolescence as the brain is still developing. In this study, we investigated the consequences of maternal separation, a model of maternal neglect, on the psychotropic effects of cocaine and the neuroplasticity of the dopaminergic system. Our results show that mice exposed to maternal separation displayed attenuated behavioural sensitization, while no changes were found in the rewarding effects of cocaine in the conditioned place preference paradigm and in the reinforcing effects of cocaine in the self-administration paradigm. The evaluation of neuroplasticity in the striatal dopaminergic pathways revealed that mice exposed to maternal separation exhibited decreased protein expression levels of D2 receptors and increased levels of the transcriptional factor Nurr1. Furthermore, animals exposed to maternal separation and treated with cocaine exhibited increased DA turnover and protein expression levels of DAT and D2R, while decreased Nurr1 and Pitx3 protein expression levels were observed when compared with saline-treated mice. Taken together, our data demonstrate that maternal separation caused an impairment of cocaine-induced behavioural sensitization possibly due to a dysfunction of the dopaminergic system, a dysfunction that has been proposed as a factor of vulnerability for developing substance use disorders.This study was supported by UE MedBioinformatics project (Grant Agreement Number: 634143), MINECO (SAF2013-41761-R-FEDER and SAF2013-49076-P-FEDER), Spanish Ministry of Health (Retic-ISCIII-RD/12/0028/0024-FEDER and RETICS-ISCIII-RD 12/0028/003-FEDER and Plan Nacional sobre Drogas 2014/020), Generalitat de Catalunya (2014SGR34) and Fundación Séneca (15405/PI/10), Región de Murcia. IG-R was funded by FPI fellowship BES-2011-046655 associated to SAF2010-15793

Effects of maternal separation on the rewarding effects of cocaine in the conditioned place preference paradigm.

<p>Data are expressed as the mean (± SEM) of the score calculated in the CPP (the difference between the time spent in the compartment associated to the drug in the testing phase versus the pre-conditioning phase). N = 8–15 mice per group.</p

Effects of maternal separation on Nurr1 and Pitx3 levels in the VTA.

<p>Densitometric analysis of specific integrated optical density (percentage of control) signals normalized to the corresponding α-tubulin levels and representative Western-blotting analysis of Nurr1 (<b>A</b>) and Pitx3 (<b>B</b>) levels in the VTA. Each bar corresponds to mean ± SEM, N = 4–5 mice per group. * p<0.05, ** p<0.01 saline vs. cocaine in the same rearing group (MSEW); + p<0.05 SN vs. MSEW; & p<0.05 SN vs. MSEW treated with cocaine (3 mg/kg) (Bonferroni post-hoc test).</p

Effect of maternal separation on DAT, D2R levels and DA turnover in the NAc.

<p>(<b>A, B</b>) Densitometric analysis of specific integrated optical density (percentage of control) signals normalized to the corresponding GADPH levels and representative Western-blotting analysis of DAT and D2R in the NAc. (<b>C)</b> DA turnover (as determined by the DOPAC/DA ratio) in the NAc. Each bar corresponds to mean ± SEM, N = 4–6 mice per group. * p<0.05, ** p<0.01 saline vs. cocaine in MSEW group; + p<0.05 vs. SN group treated with saline; $ p<0.05 vs. SN group treated with cocaine (15 mg/kg) (Bonferroni post-hoc test).</p

Three-way ANOVA calculated to evaluate the effect of maternal separation on cocaine-induced locomotor sensitization.

<p>Three-way ANOVA calculated to evaluate the effect of maternal separation on cocaine-induced locomotor sensitization.</p