Cannabidiol tempers alcohol intake and neuroendocrine and behavioural correlates in alcohol binge drinking adolescent rats. Focus on calcitonin gene-related peptide's brain levels.

Alcohol binge drinking is common among adolescents and may challenge the signalling systems that process affective stimuli, including calcitonin gene-related peptide (CGRP) signalling. Here, we employed a rat model of adolescent binge drinking to evaluate reward-, social- and aversion-related behaviour, glucocorticoid output and CGRP levels in affect-related brain regions. As a potential rescue, the effect of the phytocannabinoid cannabidiol was explored. Adolescent male rats underwent the intermittent 20% alcohol two-bottle choice paradigm; at the binge day (BD) and the 24 h withdrawal day (WD), we assessed CGRP expression in medial prefrontal cortex (mPFC), nucleus accumbens (NAc), amygdala, hypothalamus and brainstem; in addition, we evaluated sucrose preference, social motivation and drive, nociceptive response, and serum corticosterone levels. Cannabidiol (40 mg/kg, i.p.) was administered before each drinking session, and its effect was measured on the above-mentioned readouts. At BD and WD, rats displayed decreased CGRP expression in mPFC, NAc and amygdala; increased CGRP levels in the brainstem; increased response to rewarding- and nociceptive stimuli and decreased social drive; reduced serum corticosterone levels. Cannabidiol reduced alcohol consumption and preference; normalised the abnormal corticolimbic CGRP expression, and the reward and aversion-related hyper-responsivity, as well as glucocorticoid levels in alcohol binge-like drinking rats. Overall, CGRP can represent both a mediator and a target of alcohol binge-like drinking and provides a further piece in the intricate puzzle of alcohol-induced behavioural and neuroendocrine sequelae. CBD shows promising effects in limiting adolescent alcohol binge drinking and rebalancing the bio-behavioural abnormalities.

CBD enhances the cognitive score of adolescent rats prenatally exposed to THC and fine-tunes relevant effectors of hippocampal plasticity.

Introduction: An altered neurodevelopmental trajectory associated with prenatal exposure to ∆-9-tetrahydrocannabinol (THC) leads to aberrant cognitive processing through a perturbation in the effectors of hippocampal plasticity in the juvenile offspring. As adolescence presents a unique window of opportunity for "brain reprogramming", we aimed at assessing the role of the non-psychoactive phytocannabinoid cannabidiol (CBD) as a rescue strategy to temper prenatal THC-induced harm. Methods: To this aim, Wistar rats prenatally exposed to THC (2 mg/kg s.c.) or vehicle (gestational days 5-20) were tested for specific indexes of spatial and configural memory in the reinforcement-motivated Can test and in the aversion-driven Barnes maze test during adolescence. Markers of hippocampal excitatory plasticity and endocannabinoid signaling-NMDAR subunits NR1 and 2A-, mGluR5-, and their respective scaffold proteins PSD95- and Homer 1-; CB1R- and the neuromodulatory protein HINT1 mRNA levels were evaluated. CBD (40 mg/kg i.p.) was administered to the adolescent offspring before the cognitive tasks. Results: The present results show that prenatal THC impairs hippocampal memory functions and the underlying synaptic plasticity; CBD is able to mitigate cognitive impairment in both reinforcement- and aversion-related tasks and the neuroadaptation of hippocampal excitatory synapses and CB1R-related signaling. Discussion: While this research shows CBD potential in dampening prenatal THC-induced consequences, we point out the urgency to curb cannabis use during pregnancy in order to avoid detrimental bio-behavioral outcomes in the offspring.

Prenatal Exposure to Δ9-Tetrahydrocannabinol Affects Hippocampus-Related Cognitive Functions in the Adolescent Rat Offspring: Focus on Specific Markers of Neuroplasticity.

Previous evidence suggests that prenatal exposure to THC (pTHC) derails the neurodevelopmental trajectories towards a vulnerable phenotype for impaired emotional regulation and limbic memory. Here we aimed to investigate pTHC effect on hippocampus-related cognitive functions and markers of neuroplasticity in adolescent male offspring. Wistar rats were exposed to THC (2 mg/kg) from gestational day 5 to 20 and tested for spatial memory, object recognition memory and reversal learning in the reinforce-motivated Can test and in the aversion-driven Barnes maze test; locomotor activity and exploration, anxiety-like behaviour, and response to natural reward were assessed in the open field, elevated plus maze, and sucrose preference tests, respectively. The gene expression levels of NMDA NR1-2A subunits, mGluR5, and their respective scaffold proteins PSD95 and Homer1, as well as CB1R and the neuromodulatory protein HINT1, were measured in the hippocampus. pTHC offspring exhibited deficits in spatial and object recognition memory and reversal learning, increased locomotor activity, increased NR1-, decreased NR2A- and PSD95-, increased mGluR5- and Homer1-, and augmented CB1R- and HINT1-hippocampal mRNA levels. Our data shows that pTHC is associated with specific impairment in spatial cognitive processing and effectors of hippocampal neuroplasticity and suggests novel targets for future pharmacological challenges.

Adolescent binge-like alcohol exposure dysregulates NPY and CGRP in rats: Behavioural and immunochemical evidence.

Alcohol binge drinking during adolescence impacts affective behaviour, possibly impinging on developing neural substrates processing affective states, including calcitonin gene-related peptide (CGRP) and neuropeptide Y (NPY). Here, we modelled binge-like alcohol exposure in adolescence, by administering 3.5 g/kg alcohol per os, within 1 h, to male adolescent rats every other day, from postnatal day 35 to 54. The effects on positive and negative affective behaviour during abstinence were explored including: consummatory behaviour and weight gain; social behaviour in the modified social interaction test; thermal nociception in the tail-flick test; psychosocial stress coping in the resident-intruder paradigm. Moreover, CGRP and NPY levels were evaluated in functionally relevant brain regions. Our data shows that binge-like intermittent alcohol administration during adolescence decreased weight gain, social preference and motivation, nociception, and active psychosocial stress coping during abstinence. In addition, intermittent alcohol-exposed rats displayed increased expression of CGRP and NPY in the prefrontal cortex and nucleus accumbens; decreased NPY levels in the amygdala; opposite changes in CGRP levels in the hypothalamus and brainstem. Overall, our data shows that adolescent binge-like alcohol exposure, through the allostatic load of alternate intoxication and withdrawal, produces long-term consequences in sensory and affective processes and dysregulated complementary neuropeptidergic systems. Thus, neuropeptide-targeted interventions hold promising potential for addressing negative affect during prolonged withdrawal in young subjects.

Social stress under binge-like alcohol withdrawal in adolescence: evidence of cannabidiol effect on maladaptive plasticity in rats.

BACKGROUND: Alcohol binge drinking may compromise the functioning of the nucleus accumbens (NAc), i.e. the neural hub for processing reward and aversive responses. METHODS: As socially stressful events pose particular challenges at developmental stages, this research applied the resident-intruder paradigm as a model of social stress, to highlight behavioural neuroendocrine and molecular maladaptive plasticity in rats at withdrawal from binge-like alcohol exposure in adolescence. In search of a rescue agent, cannabidiol (CBD) was selected due to its favourable effects on alcohol- and stress-related harms. RESULTS: Binge-like alcohol exposed intruder rats displayed a compromised defensive behaviour against the resident and a blunted response of the stress system, in addition to indexes of abnormal dopamine (DA)/glutamate plasticity and dysfunctional spine dynamics in the NAc. CBD administration (60 mg/kg) was able to: (1) increase social exploration in the binge-like alcohol exposed intruder rats, at the expenses of freezing time, and in control rats, which received less aggressive attacks from the resident; (2) reduce corticosterone levels independently on alcohol previous exposure; (3) restore DA transmission and (4) facilitate excitatory postsynaptic strength and remodelling. CONCLUSIONS: Overall, the maladaptive behavioural and synaptic plasticity promoted by the intersection between binge-like alcohol withdrawal and exposure to adverse social stress can be rescued by a CBD détente effect that results in a successful defensive strategy, supported by a functional endocrine and synaptic plasticity. The current data highlight CBD's relevant therapeutic potential in alcohol- and stress-related harms, and prompt further investigation on its molecular targets.

BDNF as a Mediator of Antidepressant Response: Recent Advances and Lifestyle Interactions.

Conventional antidepressants are widely employed in several psychiatric and neurologic disorders, yet the mechanisms underlying their delayed and partial therapeutic effects are only gradually being understood. This narrative review provides an up-to-date overview of the interplay between antidepressant treatment and Brain-Derived Neurotrophic Factor (BDNF) signaling. In addition, the impact of nutritional, environmental and physiological factors on BDNF and the antidepressant response is outlined. This review underlines the necessity to include information on lifestyle choices in testing and developing antidepressant treatments in the future.

Alcohol binge drinking in adolescence and psychological profile: Can the preclinical model crack the chicken-or-egg question?

During adolescence, internal and external factors contribute to engaging with alcohol binge drinking (ABD), putting at risk the neurodevelopment of brain regions crucial for emotional control and stress coping. This research assessed the prevalence of ABD in late adolescent students of Southern Italy and characterized their psychological profile and drinking motives. Translational effects of alcohol binge drinking in the animal model were also studied. Seven hundred and fifty-nine high school students of both sexes (aged 18-20) were recruited. Alcohol Use Disorder Identification Test-Consumption (AUDIT-C), Drinking Motives Questionnaire-Revised Short Form, Millon Clinical Multiaxial Inventory-Third Ed., State-Trait Anxiety Inventory, Connor-Davidson Resilience Scale, and Basic Self-Esteem Scale identified alcohol habits, drinking motives, and psychopathological profile. Eighty-five percentage of the students drank alcohol and 28% of them engaged in ABD; AUDIT-C correlated with enhancement, coping, and conformity motives. ABD was related to a greater likelihood of presenting clinical syndromes and personality disorders, as well as low resilience and self-esteem. Thereafter, in the pre-clinical model, adolescent male rats were exposed to alcohol (3.5 g/kg) in an intermittent binge-like paradigm and tested during prolonged abstinence. Rats were evaluated for anxiety-like behavior, motivated behaviors, resilience, and stress response following a psychosocial challenge. Binge-like alcohol-exposed adolescent rats displayed high integrated z-score for social- and novelty-induced anxiety, altered motivation-driven output, decreased resilience, and a blunted HPA axis response to psychosocial stress, with respect to respective controls. Our data confirm that ABD is the chosen pattern of drinking in a significant percentage of high school students in Southern Italy, and highlights AUDIT-C score as a relevant parameter able to predict the occurrence of affective disturbances. The evidence from the preclinical model shows that ABD produces detrimental consequences in the adolescent rat brain, resulting in negative affect, emotional dysregulation, and aberrant stress response, pointing to decreasing excessive alcohol drinking as a primary goal for the global act for brain health.

Cytoprotective Effect of Idebenone through Modulation of the Intrinsic Mitochondrial Pathway of Apoptosis in Human Retinal Pigment Epithelial Cells Exposed to Oxidative Stress Induced by Hydrogen Peroxide.

Idebenone is a ubiquinone short-chain synthetic analog with antioxidant properties, which is believed to restore mitochondrial ATP synthesis. As such, idebenone is investigated in numerous clinical trials for diseases of mitochondrial aetiology and it is authorized as a drug for the treatment of Leber's hereditary optic neuropathy. Mitochondria of retinal pigment epithelium (RPE) are particularly vulnerable to oxidative damage associated with cellular senescence. Therefore, the aim of this study was to explore idebenone's cytoprotective effect and its underlying mechanism. We used a human-RPE cell line (ARPE-19) exposed to idebenone pre-treatment for 24 h followed by conditions inducing H2O2 oxidative damage for a further 24 h. We found that idebenone: (a) ameliorated H2O2-lowered cell viability in the RPE culture; (b) activated Nrf2 signaling pathway by promoting Nrf2 nuclear translocation; (c) increased Bcl-2 protein levels, leaving unmodified those of Bax, thereby reducing the Bax/Bcl-2 ratio; (d) maintained the mitochondrial membrane potential (ΔΨm) at physiological levels, preserving the functionality of mitochondrial respiratory complexes and counteracting the excessive production of ROS; and (e) reduced mitochondrial cytochrome C-mediated caspase-3 activity. Taken together, our findings show that idebenone protects RPE from oxidative damage by modulating the intrinsic mitochondrial pathway of apoptosis, suggesting its possible role in retinal epitheliopathies associated with mitochondrial dysfunction.

Neuromodulatory effect of interleukin 1ß in the dorsal raphe nucleus on individual differences in aggression.

Heightened aggressive behavior is considered as one of the central symptoms of many neuropsychiatric disorders including autism, schizophrenia, and dementia. The consequences of aggression pose a heavy burden on patients and their families and clinicians. Unfortunately, we have limited treatment options for aggression and lack mechanistic insight into the causes of aggression needed to inform new efforts in drug discovery and development. Levels of proinflammatory cytokines in the periphery or cerebrospinal fluid were previously reported to correlate with aggressive traits in humans. However, it is still unknown whether cytokines affect brain circuits to modulate aggression. Here, we examined the functional role of interleukin 1ß (IL-1ß) in mediating individual differences in aggression using a resident-intruder mouse model. We found that nonaggressive mice exhibit higher levels of IL-1ß in the dorsal raphe nucleus (DRN), the major source of forebrain serotonin (5-HT), compared to aggressive mice. We then examined the effect of pharmacological antagonism and viral-mediated gene knockdown of the receptors for IL-1 within the DRN and found that both treatments consistently increased aggressive behavior of male mice. Aggressive mice also exhibited higher c-Fos expression in 5-HT neurons in the DRN compared to nonaggressive mice. In line with these findings, deletion of IL-1 receptor in the DRN enhanced c-Fos expression in 5-HT neurons during aggressive encounters, suggesting that modulation of 5-HT neuronal activity by IL-1ß signaling in the DRN controls expression of aggressive behavior.

Binge-like Alcohol Exposure in Adolescence: Behavioural, Neuroendocrine and Molecular Evidence of Abnormal Neuroplasticity and Return.

Binge alcohol consumption among adolescents affects the developing neural networks underpinning reward and stress processing in the nucleus accumbens (NAc). This study explores in rats the long-lasting effects of early intermittent exposure to intoxicating alcohol levels at adolescence, on: (1) the response to natural positive stimuli and inescapable stress; (2) stress-axis functionality; and (3) dopaminergic and glutamatergic neuroadaptation in the NAc. We also assess the potential effects of the non-intoxicating phytocannabinoid cannabidiol, to counteract (or reverse) the development of detrimental consequences of binge-like alcohol exposure. Our results show that adolescent binge-like alcohol exposure alters the sensitivity to positive stimuli, exerts social and novelty-triggered anxiety-like behaviour, and passive stress-coping during early and prolonged withdrawal. In addition, serum corticosterone and hypothalamic and NAc corticotropin-releasing hormone levels progressively increase during withdrawal. Besides, NAc tyrosine hydroxylase levels increase at late withdrawal, while the expression of dopamine transporter, D1 and D2 receptors is dynamically altered during binge and withdrawal. Furthermore, the expression of markers of excitatory postsynaptic signaling-PSD95; Homer-1 and -2 and the activity-regulated spine-morphing proteins Arc, LIM Kinase 1 and FOXP1-increase at late withdrawal. Notably, subchronic cannabidiol, during withdrawal, attenuates social- and novelty-induced aversion and passive stress-coping and rectifies the hyper-responsive stress axis and NAc dopamine and glutamate-related neuroplasticity. Overall, the exposure to binge-like alcohol levels in adolescent rats makes the NAc, during withdrawal, a locus minoris resistentiae as a result of perturbations in neuroplasticity and in stress-axis homeostasis. Cannabidiol holds a promising potential for increasing behavioural, neuroendocrine and molecular resilience against binge-like alcohol harmful effects.

Social Interactions of Dat-Het Epi-Genotypes Differing for Maternal Origins: The Development of a New Preclinical Model of Socio-Sexual Apathy.

Social interaction is essential for life but is impaired in many psychiatric disorders. We presently focus on rats with a truncated allele for dopamine transporter (DAT). Since heterozygous individuals possess only one non-mutant allele, epigenetic interactions may unmask latent genetic predispositions. Homogeneous "maternal" heterozygous offspring (termed MAT-HET) were born from dopamine-transporter knocked-out (DAT-KO) male rats and wild-type (WT) mothers; "mixed" heterozygous offspring (termed MIX-HET) were born from both DAT-heterozygous parents. Their social behavior was assessed by: partner-preference (PPT), social-preference (SPT) and elicited-preference (EPT) tests. During the PPT, focal MIX-HET and MAT-HET males had a choice between two WT females, one in estrous and the other not. In the SPT, they met as stimulus either a MIX-HET or a WT male. In the EPT, the preference of focal male WT rats towards either a MIX- or a MAT-HET stimulus was tested. MIX-HET focal males showed an abnormal behavior, seeming not interested in socializing either with a female in estrous or with another male if MIX-HET. Focal MAT-HET males, instead, were very attracted by the female in estrous, but totally ignored the MIX-HET male. We assessed the expression of noradrenaline transporter (NET) in prefrontal cortex, hippocampus and hypothalamus, finding differences between the two offspring. MIX-HETs' hypothalamus and hippocampus showed less NET than MAT-HETs, while the latter, in turn, showed higher NET than WTs. These behavioral differences between heterozygous groups may be attributed to different maternal cares received. Results allow preclinical understanding of epigenetic factors involved in social-behavior abnormalities, typical of many psychiatric disorders.

Detection of a temporal structure in the rat behavioural response to an aversive stimulation in the emotional object recognition (EOR) task.

Aim of the research was to investigate whether a temporal structure could be detected in the behavioural response to an aversive stimulation. A fear-related memory task was used in rats, placed in a modified version of the Novel Object Recognition task known as Emotional Object Recognition task, i.e. a behavioural assay that orbits around the declarative memory for an aversive experience. To this purpose, twelve male Wistar rats, divided in two groups (Control and Aversive memory), observed after 4 h (OR4h) and after 24 h (OR24h) from the delivery of an aversive stimulation, associated to a specific object, were used. Data were evaluated both in terms of conventional quantitative approaches and by means of T-pattern analysis, namely a multivariate technique able to unveil the temporal structure of behaviour and the relationships amongst the behavioural items in time. Results evidenced several changes between groups and over time as well. Mean occurrences and mean durations showed significant differences between OR4h and OR24h sessions and between Control and Aversive memory groups for behavioural items of Exploration, Object-related aversion and Immobility. T-pattern analysis revealed important changes of behavioural variability, complexity and repetitiveness, (i.e., the three main qualitative features of T-patterns) in the Aversive memory group. These outcomes highlight a simpler and linear behavioural profile, focused only on specific sequences of particularly repetitive events. Overall, the present study demonstrates a) the presence of a temporal organization of fear-related behavioural events and b) the influence of learning on the modifications observed over time.

A new "sudden fright paradigm" to explore the role of (epi)genetic modulations of the DAT gene in fear-induced avoidance behavior.

Alterations in dopamine (DA) reuptake are involved in several psychiatric disorders whose symptoms can be investigated in knock out rats for the DA transporter (DAT-KO). Recent studies evidenced the role of epigenetic DAT modulation in depressive-like behavior. Accordingly, we used heterozygous (HET) rats born from both HET parents (termed MIX-HET), compared to HET rats born from WT-mother and KO-father (MAT-HET), implementing the role of maternal care on DAT modulation. We developed a "sudden fright" paradigm (based on dark-light test) to study reaction to fearful inputs in the DAT-KO, MAT-HET, MIX-HET, and WT groups. Rats could freely explore the whole 3-chambers apparatus; then, they were gently confined in one room where they experienced the fright; finally, they could freely move again. As expected, after the fearful stimulus only MAT-HET rats showed a different behavior consisting of avoidance towards the fear-associated chamber, compared to WT rats. Furthermore, ex-vivo immuno-fluorescence reveals higher prefrontal DAT levels in MAT-HET compared to MIX-HET and WT rats. Immuno-fluorescence shows also a different histone deacetylase (HDAC) enzymes concentration. Since HDAC concentration could modulate gene expression, within MAT-HET fore brain, the enhanced expression of DAT could well impair the corticostriatal-thalamic circuit, thus causing aberrant avoidance behavior (observed only in MAT-HET rats). DAT expression seems to be linked to a simply different breeding condition, which points to a reduced care by HET dams for epigenetic regulation. This could imply significant prefronto-cortical influences onto the emotional processes: hence an excessively frightful response, even to mild stressful agents, may draw developmental trajectories toward anxious and depressed-like behavior.

Environmental Enrichment During Adolescence Mitigates Cognitive Deficits and Alcohol Vulnerability due to Continuous and Intermittent Perinatal Alcohol Exposure in Adult Rats.

Perinatal alcohol exposure affects ontogenic neurodevelopment, causing physical and functional long-term abnormalities with limited treatment options. This study investigated long-term consequences of continuous and intermittent maternal alcohol drinking on behavioral readouts of cognitive function and alcohol vulnerability in the offspring. The effects of environmental enrichment (EE) during adolescence were also evaluated. Female rats underwent continuous alcohol drinking (CAD)-or intermittent alcohol drinking paradigm (IAD), along pregestation, gestation, and lactation periods-equivalent to the whole gestational period in humans. Male offspring were reared in standard conditions or EE until adulthood and were then assessed for declarative memory in the novel object recognition test; spatial learning, cognitive flexibility, and reference memory in the Morris water maze (MWM); alcohol consumption and relapse by a two-bottle choice paradigm. Our data show that perinatal CAD decreased locomotor activity, exploratory behavior, and declarative memory with respect to controls, whereas perinatal IAD displayed impaired declarative memory and spatial learning and memory. Moreover, both perinatal alcohol-exposed offspring showed higher vulnerability to alcohol consummatory behavior than controls, albeit perinatal IAD rats showed a greater alcohol consumption and relapse behavior with respect to perinatal-CAD progeny. EE ameliorated declarative memory in perinatal CAD, while it mitigated spatial learning and reference memory impairment in perinatal-IAD progeny. In addition, EE decreased vulnerability to alcohol in both control and perinatal alcohol-exposed rats. Maternal alcohol consumption produces drinking pattern-related long-term consequences on cognition and vulnerability to alcohol in the offspring. However, increased positive environmental stimuli during adolescence may curtail the detrimental effects of developmental alcohol exposure.

Increased functional connectivity in gambling disorder correlates with behavioural and emotional dysregulation: Evidence of a role for the cerebellum.

Gambling disorder (GD) is a psychiatric disease that has been recently classified as a behavioural addiction. So far, a very few studies have investigated the alteration of functional connectivity in GD patients, thus the concrete interplay between relevant function-dependent circuitries in such disease has not been comprehensively assessed. The aim of this research was to investigate resting-state functional connectivity in GD patients, searching for a correlation with GD symptoms severity. GD patients were assessed for gambling behaviour, impulsivity, cognitive distortions, anxiety and depression, in comparison with healthy controls (HC). Afterwards, they were assessed for resting-state functional magnetic resonance imaging; functional connectivity was assessed through a data-driven approach, by using independent component analysis. The correlation between gambling severity and the strength of specific resting-state networks was also investigated. Our results show that GD patients displayed higher emotional and behavioural impairment than HC, together with an increased resting state functional connectivity in the network including anterior cingulate cortex, the caudate nucleus and nucleus accumbens, and within the cerebellum, in comparison with the control group. Moreover, a significant correlation between behavioural parameters and the strength of the resting-state cerebellar network was found. Overall, the functional alterations in brain connectivity involving the cerebellum observed in this study underpin the emotional and behavioural impairment recorded in GD patients. This evidence suggests the employment of novel neuromodulatory therapeutic approaches involving specific and salient targets such as the cerebellum in addictive disorders.

In utero Δ9-tetrahydrocannabinol exposure confers vulnerability towards cognitive impairments and alcohol drinking in the adolescent offspring: Is there a role for neuropeptide Y?

BACKGROUND: Cannabinoid consumption during pregnancy has been increasing on the wave of the broad-based legalisation of cannabis in Western countries, raising concern about the putative detrimental outcomes on foetal neurodevelopment. Indeed, since the endocannabinoid system regulates synaptic plasticity, emotional and cognitive processes from early stages of life interfering with it and other excitability endogenous modulators, such as neuropeptide Y (NPY), might contribute to the occurrence of a vulnerable phenotype later in life. AIMS: This research investigated whether in utero exposure to Δ9-tetrahydrocannabinol (THC) may induce deficits in emotional/cognitive processes and alcohol vulnerability in adolescent offspring. NPY and excitatory postsynaptic density (PSD) machinery were measured as markers of neurobiological vulnerability. METHODS: Following in utero THC exposure (2 mg/kg delivered subcutaneously), preadolescent male rat offspring were assessed for: behavioural reactivity in the open field test, neutral declarative memory and aversive limbic memory in the Novel Object and Emotional Object Recognition tests, immunofluorescence for NPY neurons and the PSD proteins Homer-1, 1b/c and 2 in the prefrontal cortex, amygdala and nucleus accumbens at adolescence (cohort 1); and instrumental learning, alcohol taking, relapse and conflict behaviour in the operant chamber throughout adolescence until early adulthood (cohort 2). RESULTS: In utero THC-exposed adolescent rats showed: (a) increased locomotor activity; (b) no alteration in neutral declarative memory; (c) impaired aversive limbic memory; (d) decreased NPY-positive neurons in limbic regions; (e) region-specific variations in Homer-1, 1b/c and 2 immunoreactivity; (f) decreased instrumental learning and increased alcohol drinking, relapse and conflict behaviour in the operant chamber. CONCLUSION: Gestational THC impaired the formation of memory traces when integration between environmental encoding and emotional/motivational processing was required and promoted the development of alcohol-addictive behaviours. The abnormalities in NPY signalling and PSD make-up may represent the common neurobiological background, suggesting new targets for future research.

Motor Transitions' Peculiarity of Heterozygous DAT Rats When Offspring of an Unconventional KOxWT Mating.

Causal factors of psychiatric diseases are unclear, due to gene × environment interactions. Evaluation of consequences, after a dopamine-transporter (DAT) gene knock-out (DAT-KO), has enhanced our understanding into the pathological dynamics of several brain disorders, such as Attention-Deficit/Hyperactivity and Bipolar-Affective disorders. Recently, our attention has shifted to DAT hypo-functional (heterozygous, HET) rodents: HET dams display less maternal care and HET females display marked hypo-locomotion if cared by HET dams (Mariano et al., 2019). We assessed phenotypes of male DAT-heterozygous rats as a function of their parents: we compared "maternal" origin (MAT-HET, obtained by breeding KO-male rats with WT-female dams) to "mixed" origin (MIX-HET, obtained by classical breeding, both heterozygous parents) of the allele. MAT-HET subjects had significantly longer rhythms of daily locomotor activity than MIX-HET and WT-control subjects. Furthermore, acute methylphenidate (MPH: 0, 1, 2 mg/kg) revealed elevated threshold for locomotor stimulation in MAT-HETs, with no response to the lower dose. Finally, by Porsolt-Test, MAT-HETs showed enhanced escape-seeking (diving) with more transitions towards behavioral despair (floating). When comparing both MAT- and MIX-HET to WT-control rats, decreased levels of DAT and HDAC4 were evident in the ventral-striatum; moreover, with respect to MIX-HET subjects, MAT-HET ones displayed increased DAT density in dorsal-striatum. MAT-HET rats displayed region-specific changes in DAT expression, compared to "classical" MIX-HET subjects: greater DAT availability may elevate threshold for dopamine action. Further behavioral and epigenetic characterizations of MAT-HETs, together with deeper characterization of maternal roles, could help to explore parent-of-origin mechanisms for such a peculiar phenotype.

Targeting the Stress System During Gestation: Is Early Handling a Protective Strategy for the Offspring?

The perinatal window is a critical developmental time when abnormal gestational stimuli may alter the development of the stress system that, in turn, influences behavioral and physiological responses in the newborns. Individual differences in stress reactivity are also determined by variations in maternal care, resulting from environmental manipulations. Despite glucocorticoids are the primary programming factor for the offspring's stress response, therapeutic corticosteroids are commonly used during late gestation to prevent preterm negative outcomes, exposing the offspring to potentially aberrant stress reactivity later in life. Thus, in this study, we investigated the consequences of one daily s.c. injection of corticosterone (25 mg/kg), from gestational day (GD) 14-16, and its interaction with offspring early handling, consisting in a brief 15-min maternal separation until weaning, on: (i) maternal behavior; and (ii) behavioral reactivity, emotional state and depressive-like behavior in the adolescent offspring. Corticosterone plasma levels, under non-shock- and shock-induced conditions, were also assessed. Our results show that gestational exposure to corticosterone was associated with diminished maternal care, impaired behavioral reactivity, increased emotional state and depressive-like behavior in the offspring, associated with an aberrant corticosterone response. The early handling procedure, which resulted in increased maternal care, was able to counteract the detrimental effects induced by gestational corticosterone exposure both in the behavioral- and neurochemical parameters examined. These findings highlight the potentially detrimental consequences of targeting the stress system during pregnancy as a vulnerability factor for the occurrence of emotional and affective distress in the adolescent offspring. Maternal extra-care proves to be a protective strategy that confers resiliency and restores homeostasis.

DHA protects PC12 cells against oxidative stress and apoptotic signals through the activation of the NFE2L2/HO-1 axis.

Docosahexaenoic acid (DHA) is an omega­3 polyunsaturated fatty acid, derived mainly from fish oil. It is well known that DHA is present in high concentrations in nervous tissue and plays an important role in brain development and neuroprotection. However, the molecular mechanisms underlying its role remain to be fully elucidated. In this study, to enhance our understanding of the pathophysiological role of DHA, we investigated the possible neuroprotective mechanisms of action of DHA against hydrogen peroxide (H2O2)­induced oxidative damage in a rat pheochromocytoma cell line (PC12). Specifically, we evaluated the viability, oxidation potential, and the expression and production of antioxidant/cytoprotective enzymes, and eventual apoptosis. We found that pre­treatment with DHA (24 h) protected the cells from H2O2­induced oxidative damage. In particular, pre­treatment with DHA: i) Antagonized the consistent decrease in viability observed following exposure to H2O2 for 24 h; ii) reduced the high levels of intracellular reactive oxygen species (ROS) associated with H2O2­induced oxidative stress; iii) increased the intracellular levels of enzymatic antioxidants [superoxide dismutase (SOD) and glutathione peroxidase (GSH­Px)] both under basal conditions and following H2O2 exposure; iv) augmented the intracellular levels of reduced glutathione (GSH) and ascorbic acid, while it reduced the malondialdehyde (MDA) levels under conditions of oxidative stress; v) upregulated the expression of nuclear factor (erythroid­derived 2)­like 2 (NFE2L2) and its downstream target protein, heme­oxygenase­1 (HO­1); and vi) induced an anti­apoptotic effect by decreasing Bax and increasing Bcl2 expression. These findings provide evidence suggesting that DHA is able to prevent H2O2­induced oxidative damage to PC12 cells, which is attributed to its antioxidant and anti­apoptotic effects via the regulation NFE2L2/HO­1 signaling. Therefore, DHA may play protective role in neurodegenerative diseases associated with oxidative stress.