Cannabidiol Protects against the Reinstatement of Oxycodone-Induced Conditioned Place Preference in Adolescent Male but Not Female Rats: The Role of MOR and CB1R

Cannabidiol (CBD), a phytocannabinoid, appeared to satisfy several criteria for a safe approach to preventing drug-taking behavior, including opioids. However, most successful preclinical and clinical results come from studies in adult males. We examined whether systemic injections of CBD (10 mg/kg, i.p.) during extinction of oxycodone (OXY, 3 mg/kg, i.p.) induced conditioned place preference (CPP) could attenuate the reinstatement of CPP brought about by OXY (1.5 mg/kg, i.p.) priming in adolescent rats of both sexes, and whether this effect is sex dependent. Accordingly, a priming dose of OXY produced reinstatement of the previously extinguished CPP in males and females. In both sexes, this effect was linked to locomotor sensitization that was blunted by CBD pretreatments. However, CBD was able to prevent the reinstatement of OXY-induced CPP only in adolescent males and this outcome was associated with an increased cannabinoid 1 receptor (CB1R) and a decreased mu opioid receptor (MOR) expression in the prefrontal cortex (PFC). The reinstatement of CCP in females was associated with a decreased MOR expression, but no changes were detected in CB1R in the hippocampus (HIP). Moreover, CBD administration during extinction significantly potentialized the reduced MOR expression in the PFC of males and showed a tendency to potentiate the reduced MOR in the HIP of females. Additionally, CBD reversed OXY-induced deficits of recognition memory only in males. These results suggest that CBD could reduce reinstatement to OXY seeking after a period of abstinence in adolescent male but not female rats. However, more investigation is required.

Combined treatment with Sigma1R and A2AR agonists fails to inhibit cocaine self-administration despite causing strong antagonistic accumbal A2AR-D2R complex interactions: the potential role of astrocytes

Previous studies have indicated that acute treatment with the monoamine stabilizer OSU-6162 (5 mg/kg), which has a high affinity for Sigma1R, significantly increased the density of accumbal shell D2R-Sigma1R and A2AR-D2R heteroreceptor complexes following cocaine self-administration. Ex vivo studies using the A2AR agonist CGS21680 also suggested the existence of enhanced antagonistic accumbal A2AR-D2R allosteric interactions after treatment with OSU-6162 during cocaine self-administration. However, a 3-day treatment with OSU-6162 (5 mg/kg) failed to alter the behavioral effects of cocaine self-administration. To test these results and the relevance of OSU-6162 (2.5 mg/kg) and/or A2AR (0.05 mg/kg) agonist interactions, we administered low doses of receptor agonists during cocaine self-administration and assessed their neurochemical and behavioral effects. No effects were observed on cocaine self-administration; however, marked and highly significant increases using the proximity ligation assay (PLA) were induced by the co-treatment on the density of the A2AR-D2R heterocomplexes in the nucleus accumbens shell. Significant decreases in the affinity of the D2R high- and low-affinity agonist binding sites were also observed. Thus, in low doses, the highly significant neurochemical effects observed upon cotreatment with an A2AR agonist and a Sigma1R ligand on the A2AR-D2R heterocomplexes and their enhancement of allosteric inhibition of D2R high-affinity binding are not linked to the modulation of cocaine self-administration. The explanation may be related to an increased release of ATP and adenosine from astrocytes in the nucleus accumbens shell in cocaine self-administration. This can lead to increased activation of the A1R protomer in a putative A1R-A2AR-D2R complex that modulates glutamate release in the presynaptic glutamate synapse. We hypothesized that the integration of changes in presynaptic glutamate release and postjunctional heteroreceptor complex signaling, where D2R plays a key role, result in no changes in the firing of the GABA anti-reward neurons, resulting in no reduction in cocaine self-administration in the present experiments.

Sex-specific effects of different types of prenatal stress on foetal testosterone levels and NMDA expression in mice

Prenatal stress is a critical life event often resulting in mental illnesses in the offspring. The critical developmental processes, which might trigger a cascade of molecular events resulting in mental disorders in adulthood, are still to be elucidated. Here we proposed that sex hormones, particularly testosterone, might determine the "developmental programming" of long-term consequences of prenatal stress in foetuses of both sexes. We observed that severe prenatal stress in the model of repeated corticosterone injections enhanced brain levels of corticosterone and testosterone in male foetuses. The expression of GluN1 and GluN2A, but not GluN2B NMDA receptor subunits were significantly reduced in the brain of stressed male foetuses. However, female foetuses were protected against stress effects on the brain corticosterone and testosterone levels. More moderate types of stress, such as repeated restraint stress and chronic unpredictable stress, did not induce an increase in brain corticosterone in dams and testosterone concentrations in foetuses of both sexes. Moreover, chronic unpredictable stress reduced brain testosterone concentration in male foetuses. Altogether, changes in brain testosterone level might be one of the crucial mechanisms determining the development of long-term consequences of severe prenatal stress in male, but not in female foetuses. Targeting this mechanism might allow to develop principally new prediction and therapeutic approaches for prenatal stress-associated psychiatric disorders.

Trait sensitivity to negative feedback in rats is associated with increased expression of serotonin 5-HT2A receptors in the ventral hippocampus

One of the most important yet still underappreciated mechanisms of depression is distorted cognition, with aberrant sensitivity to negative feedback being one of the best-described examples. As serotonin has been identified as an important modulator of sensitivity to feedback and because the hippocampus has been implicated in the mediation of learning from positive and negative outcomes, the present study aimed to identify differences in the expression of various genes encoding 5-HT receptors in this brain region between the rats displaying trait sensitivity and insensitivity to negative feedback. The results demonstrated that trait sensitivity to negative feedback is associated with increased mRNA expression of the 5-HT2A receptors in the rat ventral hippocampus (vHipp). Further analysis revealed that this increased expression might be modulated epigenetically by miRNAs with a high target score for the Htr2a gene (miR-16-5p and miR-15b-5p). Additionally, although not confirmed at the protein level, trait sensitivity to negative feedback was associated with decreased expression of mRNA encoding the 5-HT7 receptor in the dorsal hippocampus (dHipp). We observed no statistically significant intertrait differences in the expression of the Htr1a, Htr2c, and Htr7 genes in the vHipp and no statistically significant intertrait differences in the expression of the Htr1a, Htr2a, and Htr2c genes in the dHipp of the tested animals. These results suggest that resilience to depression manifested by reduced sensitivity to negative feedback may be mediated via these receptors.

Impact of Mephedrone on Fear Memory in Adolescent Rats: Involvement of Matrix Metalloproteinase-9 (MMP-9) and N-Methyl-D-aspartate (NMDA) Receptor

Treatment of Post-Traumatic Stress Disorder (PTSD) is complicated by the presence of drug use disorder comorbidity. Here, we examine whether conditioned fear (PTSD model) modifies the rewarding effect of mephedrone and if repeated mephedrone injections have impact on trauma-related behaviors (fear sensitization, extinction, and recall of the fear reaction). We also analyzed whether these trauma-induced changes were associated with exacerbation in metalloproteinase-9 (MMP-9) and the GluN2A and GluN2B subunits of N-methyl-D-aspartate (NMDA) glutamate receptor expression in such brain structures as the hippocampus and basolateral amygdala. Male adolescent rats underwent trauma exposure (1.5 mA footshock), followed 7 days later by a conditioned place preference training with mephedrone. Next, the post-conditioning test was performed. Fear sensitization, conditioned fear, anxiety-like behavior, extinction acquisition and relapse were then assessed to evaluate behavioral changes. MMP-9, GluN2A and GluN2B were subsequently measured. Trauma-exposed rats subjected to mephedrone treatment acquired a strong place preference and exhibited impairment in fear extinction and reinstatement. Mephedrone had no effect on trauma-induced MMP-9 level in the basolateral amygdala, but decreased it in the hippocampus. GluN2B expression was decreased in the hippocampus, but increased in the basolateral amygdala of mephedrone-treated stressed rats. These data suggest that the modification of the hippocampus and basolateral amygdala due to mephedrone use can induce fear memory impairment and drug seeking behavior in adolescent male rats.

Adult alcohol drinking and emotional tone are mediated by neutral sphingomyelinase during development in males

Alcohol use, abuse, and addiction, and resulting health hazards are highly sex-dependent with unknown mechanisms. Previously, strong links between the SMPD3 gene and its coded protein neutral sphingomyelinase 2 (NSM) and alcohol abuse, emotional behavior, and bone defects were discovered and multiple mechanisms were identified for females. Here we report strong sex-dimorphisms for central, but not for peripheral mechanisms of NSM action in mouse models. Reduced NSM activity resulted in enhanced alcohol consumption in males, but delayed conditioned rewarding effects. It enhanced the acute dopamine response to alcohol, but decreased monoaminergic systems adaptations to chronic alcohol. Reduced NSM activity increased depression- and anxiety-like behavior, but was not involved in alcohol use for the self-management of the emotional state. Constitutively reduced NSM activity impaired structural development in the brain and enhanced lipidomic sensitivity to chronic alcohol. While the central effects were mostly opposite to NSM function in females, similar roles in bone-mediated osteocalcin release and its effects on alcohol drinking and emotional behavior were observed. These findings support the view that the NSM and multiple downstream mechanism may be a source of the sex-differences in alcohol use and emotional behavior.

Novel Dopamine Transporter Inhibitor, CE-123, Ameliorates Spatial Memory Deficits Induced by Maternal Separation in Adolescent Rats: Impact of Sex

Maternal separation (MS) is a key contributor to neurodevelopmental disorders, including learning disabilities. To test the hypothesis that dopamine signaling is a major factor in this, an atypical new dopamine transporter (DAT) inhibitor, CE-123, was assessed for its potential to counteract the MS-induced spatial learning and memory deficit in male and female rats. Hence, neonatal rats (postnatal day (PND)1 to 21) were exposed to MS (180 min/day). Next, the acquisition of spatial learning and memory (Barnes maze task) and the expression of dopamine D1 receptor, dopamine transporter (DAT), and the neuronal GTPase, RIT2, which binds DAT in the vehicle-treated rats were evaluated in the prefrontal cortex and hippocampus in the adolescent animals. The results show that MS impairs the acquisition of spatial learning and memory in rats, with a more severe effect in females. Moreover, the MS induced upregulation of DAT and dopamine D1 receptors expression in the prefrontal cortex and hippocampus in adolescent rats. Regarding RIT2, the expression was decreased in the hippocampus for both the males and females, however, in the prefrontal cortex, reduction was found only in the females, suggesting that there are region-specific differences in DAT endocytic trafficking. CE-123 ameliorated the behavioral deficits associated with MS. Furthermore, it decreased the MS-induced upregulation of D1 receptor expression level in the hippocampus. These effects were more noted in females. Overall, CE-123, an atypical DAT inhibitor, is able to restore cognitive impairment and dopamine signaling in adolescent rats exposed to MS—with more evident effect in females than males.

Psychiatry training goes virtual: the experience of the first online edition of the EPA Research Summer School

Introduction

The European Psychiatric Association (EPA) Summer School allows psychiatric trainees and early career psychiatrists (ECPs) from all over Europe to meet, network, and learn together. After the 2020 edition being cancelled due to COVID-19, the 10th edition in 2021 focused for the first time on research and was conducted remotely.

Objectives

To provide an overview and feedback about the first Virtual EPA Research Summer School as a new way to encourage international networking during COVID-19.

Methods

The School was organized by the EPA Secretary for Education, and 4 Faculty members. It started with a “breaking the ice session” one week before and then a two-days meeting on 23-24 September 2021 using an online video-platform. This was preceded by all the 21 participants (from 18 different countries) recording a short 4-minute video presentation, which was uploaded and shared with other participants and Faculty.

Results

Participants were divided on a voluntary basis into three working groups: 1) “Drug repurposing: overcoming challenges in pharmacoepidemiology” 2) “Psychopathological research in psychiatry”; 3) “How to conduct a cross-sectional survey?”. The Summer School program was composed of plenary sessions with lectures by the Faculty members, discussion sessions, and working groups time. At the end, each group presented a summary of the work done to the rest of the participants.

Conclusions

Although the remote format limits social interactions during the Summer School, overall participants’ high satisfaction and productivity indicate that not only online formats, but also the topic of research might be covered in future editions.

Disclosure

No significant relationships.

Maternal Separation Alters Ethanol Drinking and Reversal Learning Processes in Adolescent Rats: The Impact of Sex and Glycine Transporter Type 1 (GlyT1) Inhibitor

Adverse early life experiences are associated with an enhanced risk for mental and physical health problems, including substance abuse. Despite clinical evidence, the mechanisms underlying these relationships are not fully understood. Maternal separation (MS) is a commonly used animal model of early neglect. The aim of the current study is to determine whether the N-methyl-D-aspartate receptor (NMDAR)/glycine sites are involved in vulnerability to alcohol consumption (two-bottle choice paradigm) and reversal learning deficits (Barnes maze task) in adolescent rats subjected to the MS procedure and whether these effects are sex dependent. By using ELISA, we evaluated MS-induced changes in the NMDAR subunits (GluN1, GluN2A, GluN2B) expression, especially in the glycine-binding subunit, GluN1, in the prefrontal cortex (PFC) and ventral striatum (vSTR) of male/female rats. Next, we investigated whether Org 24598, a glycine transporter 1 (GlyT1) inhibitor, was able to modify ethanol drinking in adolescent and adult male/female rats with prior MS experience and reversal learning in the Barnes maze task. Our findings revealed that adolescent MS female rats consumed more alcohol which may be associated with a substantial increase in GluN1 subunit of NMDAR in the PFC and vSTR. Org 24598 decreased ethanol intake in both sexes with a more pronounced decrease in ethanol consumption in adolescent female rats. Furthermore, MS showed deficits in reversal learning in both sexes. Org 24598 ameliorated reversal learning deficits, and this effect was reversed by the NMDAR/glycine site inhibitor, L-701,324. Collectively, our results suggest that NMDAR/glycine sites might be targeted in the treatment of alcohol abuse in adolescents with early MS, especially females.

Memantine Prevents the WIN 55,212-2 Evoked Cross-Priming of Ethanol-Induced Conditioned Place Preference (CPP)

The activation of the endocannabinoid system controls the release of many neurotransmitters involved in the brain reward pathways, including glutamate. Both endocannabinoid and glutamate systems are crucial for alcohol relapse. In the present study, we hypothesize that N-methyl-D-aspartate (NMDA) glutamate receptors regulate the ability of a priming dose of WIN 55,212-2 to cross-reinstate ethanol-induced conditioned place preference (CPP). To test this hypothesis, ethanol-induced (1.0 g/kg, 10% w/v, i.p.) CPP (unbiased method) was established using male adult Wistar rats. After CPP extinction, one group of animals received WIN 55,212-2 (1.0 and 2.0 mg/kg, i.p.), the cannabinoid receptor 1 (CB1) agonist, or ethanol, and the other group received memantine (3.0 or 10 mg/kg, i.p.), the NMDA antagonist and WIN 55,212-2 on the reinstatement day. Our results showed that a priming injection of WIN 55,212-2 (2.0 mg/kg, i.p.) reinstated (cross-reinstated) ethanol-induced CPP with similar efficacy to ethanol. Memantine (3.0 or 10 mg/kg, i.p.) pretreatment blocked this WIN 55,212-2 effect. Furthermore, our experiments indicated that ethanol withdrawal (7 days withdrawal after 10 days ethanol administration) down-regulated the CNR1 (encoding CB1), GRIN1/2A (encoding GluN1 and GluN2A subunit of the NMDA receptor) genes expression in the prefrontal cortex and dorsal striatum, but up-regulated these in the hippocampus, confirming the involvement of these receptors in ethanol rewarding effects. Thus, our results show that the endocannabinoid system is involved in the motivational properties of ethanol, and glutamate may control cannabinoid induced relapse into ethanol seeking behavior.

The effect of myo-inositol, vitamin D3 and melatonin on the oocyte quality and pregnancy in in vitro fertilization: a randomized prospective controlled trial

OBJECTIVE

To evaluate the efficacy of a treatment with Myo-inositol (MI) plus melatonin and vitamin D3 in women underwent intra cytoplasmatic sperm injection (ICSI).

PATIENTS AND METHODS

100 women undergoing ICSI procedure were enrolled and randomly divided 1:1 in two groups. The study group was treated with 2 g MI, 50 mg Alpha-Lactalbumin (alpha-LA) and 200 µg folic acid in powder every morning for 6 months (3 months before oocyte pick up and 3 months after ICSI); the same patients underwent treatment with 600 mg MI, 1 mg melatonin plus 200 µg folic acid during the evening for 3 months before oocyte pick up; subsequently the pick up these patients were treated with 600 mg MI, 200 µg folic acid, 1 mg melatonin, 50 µg vitamin D3 as cholecalciferol until the 12th week of gestation. The control group was treated with 200 µg folic acid twice a day. Clinical pregnancy rate was evaluated as primary outcome, followed by blastocyst and oocyte quality, as well as gestational period as secondary outcomes.

RESULTS

Treatment significantly improved blastocyst and oocyte quality in the study group, achieving the 42% of clinical pregnancies vs. 24% in the control group, even though the course of pregnancy did not significantly differ between the groups. However, the mean gestational period was shorter in the control group.

CONCLUSIONS

The supplementation of MI in combination with melatonin in the first 3 months before oocyte pick up and with vitamin D3 in the further 3 months could represent an innovative support for all those women undergoing ICSI.

Neutral Sphingomyelinase is an Affective Valence-Dependent Regulator of Learning and Memory

Sphingolipids and enzymes of the sphingolipid rheostat determine synaptic appearance and signaling in the brain, but sphingolipid contribution to normal behavioral plasticity is little understood. Here we asked how the sphingolipid rheostat contributes to learning and memory of various dimensions. We investigated the role of these lipids in the mechanisms of two different types of memory, such as appetitively and aversively motivated memory, which are considered to be mediated by different neural mechanisms. We found an association between superior performance in short- and long-term appetitively motivated learning and regionally enhanced neutral sphingomyelinase (NSM) activity. An opposite interaction was observed in an aversively motivated task. A valence-dissociating role of NSM in learning was confirmed in mice with genetically reduced NSM activity. This role may be mediated by the NSM control of N-methyl-d-aspartate receptor subunit expression. In a translational approach, we confirmed a positive association of serum NSM activity with long-term appetitively motivated memory in nonhuman primates and in healthy humans. Altogether, these data suggest a new sphingolipid mechanism of de-novo learning and memory, which is based on NSM activity.

The Positive and Negative Outcome of Morphine and Disulfiram Subacute Co-Administration in Rats in the Absence of Ethanol Challenge

Recently, a well-known anti-alcohol agent, disulfiram (DSF), has gain much interest, as it was found to be effective in the treatment of cocaine abusers, thus also giving hope for patients addicted to opioids and other illicit drugs. Therefore, this study was aimed to investigate the possible outcome that might occur within the subacute co-administration of both morphine (MRF) and DSF in rats, but in the absence of ethanol challenge. As observed, intraperitoneal DSF dose-dependently enhanced MRF-mediated analgesia with the maximal efficacy at a dose of 100 mg/kg. Furthermore, MRF-induced tolerance and aggressive behavior were significantly reduced by DSF (100 mg/kg, i.p.) in comparison to MRF solely. Nonetheless, significant blood biochemical markers of hepatotoxicity were found (i.e., alteration in the levels of glutathione, blood urea nitrogen, etc.), following a combination of both drugs. Likewise, histological analysis of liver tissue revealed severe changes in the group of DSF + MRF, which includes swelling, cell death, damage to certain vessels, and hemorrhages into the liver parenchyma. Our findings indicate that DSF should be used with extreme caution, especially within the course of subacute concomitant use with MRF, as several possible side effects may take place.

The impact of 3,4-methylendioxymetamphetamine (MDMA) abstinence on seeking behavior and the expression of the D2-like and mGlu5 receptors in the rat brain using saturation binding analyses

The abundance of research indicates that enriched environment acts as a beneficial factor reducing the risks of relapse in substance use disorder. There is also strong evidence showing the engagement of brain dopaminergic and glutamatergic signaling through the dopamine D₂-like and metabotropic glutamate type 5 (mGlu₅) receptors, respectively, that has a direct impact on drug reward and drug abstinence. The present study involved 3,4-methylendioxymethamphetamine (MDMA) self-administration with the yoked-triad procedure in rats kept under different housing conditions during abstinence - enriched environment (EE) or isolation cage (IC) conditions - aimed at evaluating changes in brain receptors affecting drug-seeking behavior as well as density and affinity of the D₂-like and mGlu₅ receptors in several regions of the animal brain. Our results show that exposure to EE conditions strongly reduced active lever presses during cue-induced drug-seeking. At the neurochemical level, we demonstrated marked decreases of D₂-like receptor affinity in the dorsal striatum in rats previously self-administering MDMA under EE and increases in density under IC conditions. Moreover, we found the increases in the density and decreases in the affinity of the D₂-like receptor in the prefrontal cortex and nucleus accumbens provoked by IC conditions. The mGlu₅ receptor density decreased only in the prefrontal cortex after IC and EE abstinence. Moreover, our study has revealed a clear decrease in mGlu₅ receptor density in the nucleus accumbens in the group actively administering MDMA only under EE conditions. This study demonstrates that housing conditions have impact on drug-seeking behavior in rats during abstinence from MDMA self-administration. The observed changes in the dopamine D₂-like and mGlu₅ receptor B_max and/or K_d values were brain-region specific and related to either pharmacological and/or motivational features of MDMA.

Molecular changes evoked by the beta-lactam antibiotic ceftriaxone across rodent models of substance use disorder and neurological disease

Ceftriaxone is a beta-lactam antibiotic that increases the expression of the major glutamate transporter, GLT-1. As such, ceftriaxone ameliorates symptoms across multiple rodent models of neurological diseases and substance use disorders. However, the mechanism behind GLT-1 upregulation is unknown. The present review synthesizes this literature in order to identify commonalities in molecular changes. We find that ceftriaxone (200 mg/kg for at least two days) consistently restores GLT-1 expression in multiple rodent models of neurological disease, especially when GLT-1 is decreased in the disease model. The same dose given to healthy/drug-naive rodents does not reliably upregulate GLT-1 in any brain region except the hippocampus. Increased GLT-1 expression does not consistently arise from transcriptional regulation, and is likely to be due to trafficking changes. In addition to altered transporter expression, ceftriaxone ameliorates neuropathologies (e.g. tau, amyloid beta, cell death) and aberrant protein expression associated with a number of neurological disease models. Taken together, these results indicate that ceftriaxone remains a strong candidate for treatment of multiple disorders in the clinic.

[Minimally Invasive Posterior Lumbar Interbody Fusion and Instrumentation - Outcomes at 24-Month Follow-up]

PURPOSE OF THE STUDY Minimally invasive posterior lumbar interbody fusion and percutaneous instrumentation were introduced in the clinical practice with the aim to reduce the damage to musculoligamentous structures associated with open surgeries. The purpose of the study is to evaluate the clinical outcomes, radiological results and complications of the group of patients operated with the use of the minimally invasive posterior lumbar interbody fusion technique. MATERIAL AND METHODS The group of 31 patients operated for lumbar degenerative disc disease was followed-up prospectively. The surgical technique included a unilateral microsurgical decompression of the spinal canal with the insertion of interbody cages supplemented by percutaneous transpedicular fixation. The clinical outcomes were evaluated by means of the Oswestry Disability Index (ODI), Macnab classification, VAS score for low back pain (VAS LBP) and lower extremity pain (VAS LE) at 2, 6, 12 and 24 months postoperatively. The success rate of interbody fusion and complications was also assessed. RESULTS The inclusion criteria were met by 29 patients. The mean preoperative ODI score of 68.4 decreased to 25.1 at two-year follow-up (p 0.001). Based on the modified Macnab scale excellent and good outcomes were achieved at two-year-followup by 82.4% patients. The mean value of VAS LBP score decreased from 6.2 to 2.1 and in case of VAS LE from 5.38 to 1.34 (p ˂ 0.001). The mean time of operation was 157 minutes. Solid interbody fusion was achieved in 80% of patients. In one case, revision surgery for dislocation of the interbody cage was performed one year after the operation. A total of five misplaced transpedicular screws (5.2%) were recorded. DISCUSSION Dorsal minimally invasive spinal operational techniques, when compared with the open surgery, result in less iatrogenic injury to paravertebral muscles. From a short-term perspective, there is also less blood loss and lower frequency of infectious complications. Together with the reduction of postoperative pain and shorter hospital stay, they enable faster recovery and rehabilitation with comparable clinical effectiveness of the procedure. Apart from the above-mentioned benefits, also some shortcomings are discussed such as higher frequency of complications, longer time of operation, higher occurrence of implant malposition and higher exposure of the patient and the surgeon to radiation. CONCLUSIONS The minimally invasive posterior lumbar interbody fusion technique resulted in a statistically significant clinical improvement in the ODI, Macnab scale, VAS LBP and VAS LE scores. The percutaneous instrumentation technique shows an acceptable rate of incorrectly inserted screws. Key words: degenerative disc disease, minimally invasive spinal surgery, posterior lumbar interbody fusion, spine stabilization, lumbar interbody fusion complications.

Brain region-dependent changes in the expression of endocannabinoid-metabolizing enzymes in rats following antidepressant drugs

The endocannabinoid (eCB) system plays a role in the pathophysiology of depression. The aim of this study was to investigate the expression of the eCB synthesizing enzymes (N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) and diacylglycerol lipase α (DAGLα)) and eCB degrading enzymes (fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL)) after acute or chronic administration of antidepressant drugs (imipramine (IMI, 15 mg/kg), escitalopram (ESC, 10 mg/kg) and tianeptine (TIA, 10 mg/kg)). eCB metabolizing enzymes were altered in drug-dependent and brain region-specific fashion. After IMI treatment a reduction was noted in the expression of FAAH protein in the dorsal striatum, MAGL in the frontal cortex and DAGLα in the cerebellum. On the other hand, ESC treatment provoked an increase in the MAGL expression in the prefrontal cortex or NAPE-PLD and in DAGLα in the hippocampus and dorsal striatum, while reducing the FAAH expression in the dorsal striatum. TIA administration increased the levels of all enzymes in the prefrontal cortex as well as elevated DAGLα expression in the frontal cortex and dorsal striatum. In conclusion, our results indicate that changes in the eCBs levels after antidepressant drug treatment were related to the expression of their metabolizing enzymes.

Acute Cocaine Enhances Dopamine D2R Recognition and Signaling and Counteracts D2R Internalization in Sigma1R-D2R Heteroreceptor Complexes

The current study was performed to establish the actions of nanomolar concentrations of cocaine, not blocking the dopamine transporter, on dopamine D2 receptor (D2R)-sigma 1 receptor (δ1R) heteroreceptor complexes and the D2R protomer recognition, signaling and internalization in cellular models. We report the existence of D2R-δ1R heteroreceptor complexes in subcortical limbic areas as well as the dorsal striatum, with different distribution patterns using the in situ proximity ligation assay. Also, through BRET, these heteromers were demonstrated in HEK293 cells. Furthermore, saturation binding assay demonstrated that in membrane preparations of HEK293 cells coexpressing D2R and δ1R, cocaine (1 nM) significantly increased the D2R Bmax values over cells singly expressing D2R. CREB reporter luc-gene assay indicated that coexpressed δ1R significantly reduced the potency of the D2R-like agonist quinpirole to inhibit via D2R activation the forskolin induced increase of the CREB signal. In contrast, the addition of 100 nM cocaine was found to markedly increase the quinpirole potency to inhibit the forskolin-induced increase of the CREB signal in the D2R-δ1R cells. These events were associated with a marked reduction of cocaine-induced internalization of D2R protomers in D2R-δ1R heteromer-containing cells vs D2R singly expressing cells as studied by means of confocal analysis of D2R-δ1R trafficking and internalization. Overall, the formation of D2R-δ1R heteromers enhanced the ability of cocaine to increase the D2R protomer function associated with a marked reduction of its internalization. The existence of D2R-δ1R heteromers opens up a new understanding of the acute actions of cocaine.

Maternal high-fat diet during pregnancy and lactation provokes depressive-like behavior and influences the irisin/brain-derived neurotrophic factor axis and inflammatory factors in male and female offspring in rats

A balanced maternal diet is necessary for the proper health and development of offspring. Recent clinical and preclinical studies have strongly indicated that maternal exposure to a high-fat diet (HFD) can have an irreversible impact on the structure and function of the offspring's brain and affect the immune system, which may predispose the offspring to brain disorders, including depression. The irisin/brain-derived neurotrophic factor (BDNF) axis is a pathway that influences several neurobehavioral mechanisms involved in the pathogenesis of mental disorders. The aim of the present study was to evaluate the influence of a maternal HFD during pregnancy and lactation on depressive-like behavior, serum irisin concentration and hippocampal levels of irisin, BDNF and inflammatory factors (interleukin-1α, interleukin-6 and tumor necrosis factor-α) in adolescent and adult male and female offspring. The main findings indicate that offspring exposed to a maternal HFD are characterized by an increased immobility time in the forced swimming test at both stages of life. Our results showed that a maternal HFD decreased serum and hippocampal irisin levels in females on postnatal day (PND) 28 and decreased the level of interleukin-1α at postnatal days 28 and 63 in the hippocampus. Interestingly, significant age-dependent changes were observed in irisin, BDNF and interleukin levels. To summarize, our study indicates that a maternal HFD during pregnancy and lactation provokes depressive-like behaviour in the offspring. However, despite the observed changes in the levels of irisin and IL-1α in females, further investigations are required to identify the underlying molecular mechanism associated with depressive-like behavior in the offspring of HFD-fed dams.

Regorafenib therapy in metastatic colorectal cancer patients: markers and outcome in an actual clinical setting

The oral multikinase inhibitor regorafenib had beneficial effects in randomized clinical phase III trials compared to the placebo in patients with metastatic colorectal cancer (mCRC) who progressed on standard therapies. The factors which influence regorafenib response and therapy sequence during treatment history are still highly discussed, and herein we analyzed the therapy algorithm, outcome and clinical markers following regorafenib application in a single center register study. Clinical data for 48 metastatic colorectal cancer patients were collected from 01.01.2013 to 31.12.2016. Treatment effects according to various patient and tumor characteristics were evaluated using univariate and multivariate Cox proportional hazard regression models. The 48 patients comprised 14 (29%) females and 34 (71%) males, with mean age 64.2±9 and ECOG 0-1. Progression free survival under regorafenib therapy was 2.9 months (quartiles 2.2; 4.4) and the overall response rate was 2 (4%) and disease control rate was 19 (40%). Overall survival (OS) and progression free survival (PFS) were investigated under regorafenib in the chemotherapy regimen given immediately before and afterthis treatment. Variables including tumor localization, Ras status, CEA and CA 19-9 plasma levels were analyzed for their impact on PFS, and the regorafenib-related adverse events were also observed. Our study confirms the efficacy of regorafenib in a real-life setting. We established that response rate and PFS in regorafenib treatment are independent of tumor localization, Ras status or biomarkers such as CEA and CA 19-9. Trifluridin/tripacil application or re-induction of chemotherapy +/- target therapy was effective following regorafenib therapy.

[First Experience with Cranioplasty Using the Polyetheretherketone (PEEK) Implant - Retrospective Five-Year Follow-up Study]

PURPOSE OF THE STUDY Cranioplasty is currently the most common neurosurgical procedure. The purpose of this study is to describe the first experience with successful use of the Cranio-Oss (PEEK) custom implant for cranioplasty. MATERIAL AND METHODS In the period 2012 to 2013, a total of 26 cranioplasties were performed. In fourteen patients, their own bone flap was used for reconstruction. In four cases, a synthetic Cranio-Oss bone implant made of PEEK was used. In six patients, the defect was covered by an intraoperatively-made Palacos implant and in two cases, minor defects were covered with a titanium mesh. The patients were followed up for at least five years. Cranio-Oss is a cranial implant made from polyetheretherketone (PEEK), a synthetic biocompatible material. The implant is created using the CAD/CAM method in the shape of the bone defect based on the CT scan. Creating optimal roughness of the implant surface and of the surface of the contact area attached to the bone bed is controlled and included already in the strategy for machining individual areas of the implant during its manufacturing at a 5-axis machining centre. RESULTS The Cranio-Oss implant was used in four younger patients to cover larger and complex-shaped defects. The mean age of patients in this group was 47 years. The implant was fixed to the skull by micro-plates. In all the cases the wound healed well with good cosmetic results without the necessity of revision with respect to the used implant. The follow-up CT scans always showed the implant in situ with no signs of malposition. DISCUSSION Autologous bone flap is the most suitable material for defect reconstruction after craniectomy. This option is affordable and represents one of the best methods of reconstruction of defects after craniectomy in terms of cosmetic results. In some cases, the original skull cannot be used for cranioplasty (e.g. if destructed by tumourous process, infected or in comminuted fractures). In such cases, the defect needs to be managed using a synthetic implant. In case of extensive defects, the most suitable option is a custom made implant from advanced biomaterials. CONCLUSIONS Authors prefer using autologous bone flaps during cranioplasty. In cases where this method is unavailable, a synthetic bone substitute has to be used. The first medium-term experience with the use of a Cranio-Oss implant made of PEEK showed that it is a suitable alternative to the patient's own bone. No complications associated with this synthetic implant were reported and its use to manage skull defects can be strongly recommended. With respect to legal and accreditationrelated difficulties connected with bone fragments storage and thanks to the continuous cost reduction of synthetic implants will their importance grow in the future. Key words: decompressive craniectomy, bone substitute, craniotrauma.

A2AR-D2R Heteroreceptor Complexes in Cocaine Reward and Addiction

The concept of allosteric receptor-receptor interactions in G protein-coupled receptor homo- and heteroreceptor complexes in which they physically interact provides a new dimension to molecular integration in the brain. The receptor-receptor interactions dynamically change recognition, pharmacology, signaling, and trafficking of the participating receptors. Among the receptor complexes, disruption of the A2A receptor-dopamine D2 receptor (A2AR-D2R) complex by an A2AR agonist has been shown to fully block the inhibition of cocaine self-administration. Cocaine induced pathological A2AR-D2R-Sigma1R complexes may form a long-term memory with a strong and permanent D2R brake, leading to cocaine addiction. These heteroreceptor complexes can potentially be targeted for future pharmacotherapy of cocaine addiction by using heterobivalent compounds or A2AR-D2R receptor interface-interfering peptides that disrupt the A2AR-D2R-Sigma1R complexes.

Disruption of A2AR-D2R Heteroreceptor Complexes After A2AR Transmembrane 5 Peptide Administration Enhances Cocaine Self-Administration in Rats

Antagonistic allosteric A2AR-D2R receptor-receptor interactions in heteroreceptor complexes counteract cocaine self-administration and cocaine seeking in rats as seen in biochemical and behavioral experiments. It was shown that the human A2AR transmembrane five (TM5) was part of the interface of the human A2AR-D2R receptor heteromer. In the current paper, the rat A2AR synthetic TM5 (synthTM5) peptide disrupts the A2AR-D2R heteroreceptor complex in HEK293 cells as shown by the bioluminescence resonance energy transfer method. Rat A2AR synthTM5 peptide, microinjected into the nucleus accumbens, produced a complete counteraction of the inhibitory effects of the A2AR agonist CGS21680 on cocaine self-administration. It was linked to a disappearance of the accumbal A2AR-D2R heteroreceptor complexes and the A2AR agonist induced inhibition of D2R recognition using proximity ligation assay and biochemical binding techniques. However, possible effects of the A2AR synthTM5 peptide on accumbal A2AR-D3R and A2AR-D4R heteroreceptor complexes remain to be excluded. Evidence is provided that accumbal A2AR-D2R-like heteroreceptor complexes with their antagonistic receptor-receptor interactions can be major targets for treatment of cocaine use disorder.