Abrupt cessation of reboxetine along alcohol deprivation results in alcohol intake escalation after reinstatement of drinking.

Major depression (MD) is a frequent comorbidity in alcohol use disorder (AUD) patients. Antidepressant prescription is often limited by poor clinical outcomes or unwanted side effects in comorbid AUD-MD patients. Recent studies suggest that abrupt cessation of selective serotonin reuptake inhibitors antidepressant treatment increases alcohol consumption after an alcohol deprivation period in rats. However, the appearance of this effect after the treatment with selective noradrenaline reuptake inhibitors (SNRIs) is not known. Here, we report that interruption of subchronic (14 days) treatment with the SNRIs reboxetine (15 mg/kg/day intraperitoneally) resulted in escalation of ethanol intake when the animals resume alcohol self-administration. This effect of reboxetine treatment cessation was associated with a profound deactivation of the endocannabinoid/acylethanolamide signaling system in the prefrontal cortex but not in the dorsal hippocampus, as reflected by the decrease in the protein expression of the cannabinoid CB1 receptor, the PPARα receptor, the 2-arachidonoylglycerol synthesizing enzymes DAGLα and DGALß, and the endocanabinoid degrading enzyme MAGL. This was associated with dysregulation of the expression of glutamic acid receptors GluN1, GluA1, and mGlu5 in the medial prefrontal cortex and the dorsal hippocampus of the animals exposed to reboxetine. The present results further support the idea that abrupt cessation of antidepressant therapy along alcohol deprivation time can boost alcohol intake after relapse through mechanisms associated with endocannabinoid/glutamate signaling dysregulation. This finding might be relevant for patients suffering AUD/MD comorbidity where antidepressant therapy must be monitored with caution for avoiding unwanted side effects if adherence to the treatment is not fully achieved.

Cessation of fluoxetine treatment increases alcohol seeking during relapse and dysregulates endocannabinoid and glutamatergic signaling in the central amygdala.

Administration of selective serotonin reuptake inhibitors (SSRIs), typically used as antidepressants, induces long-lasting behavioral changes associated with alcohol use disorder (AUD). However, the contribution of SSRI (fluoxetine)-induced alterations in neurobiological processes underlying alcohol relapse such as endocannabinoid and glutamate signaling in the central amygdala (CeA) remains largely unknown. We utilized an integrative approach to study the effects of repeated fluoxetine administration during abstinence on ethanol drinking. Gene expression and biochemical and electrophysiological studies explored the hypothesis that dysregulation in glutamatergic and endocannabinoid mechanisms in the CeA underlie the susceptibility to alcohol relapse. Cessation of daily treatment with fluoxetine (10 mg/kg) during abstinence resulted in a marked increase in ethanol seeking during re-exposure periods. The increase in ethanol self-administration was associated with (a) reductions in levels of the endocannabinoids N-arachidonoylethanolomine and 2-arachidonoylglycerol in the CeA, (b) increased amygdalar gene expression of cannabinoid type-1 receptor (CB1), N-acyl phosphatidylethanolamine phospholipase D (Nape-pld), fatty acid amid hydrolase (Faah), (c) decreased amygdalar gene expression of ionotropic AMPA (GluA2 and GluA4) and metabotropic (mGlu3) glutamate receptors, and (d) increased glutamatergic receptor function. Overall, our data suggest that the administration of the antidepressant fluoxetine during abstinence dysregulates endocannabinoid signaling and glutamatergic receptor function in the amygdala, facts that likely facilitate alcohol drinking behavior during relapse.

Antianhedonic and Antidepressant Effects of Affron®, a Standardized Saffron (Crocus Sativus L.) Extract.

Anxiety and depression have high prevalence in the general population, affecting millions of people worldwide, but there is still a need for effective and safe treatments. Nutritional supplements have recently received a lot of attention, particularly saffron. Thus, several pre-clinical studies support a beneficial role for bioactive compounds, such as saffron, in anxiety and depression. Here we used an animal model of depression based on social isolation to assess the effects of affron®, a standardized saffron extract containing ≥3.5% of total bioactive compounds safranal and crocin isomers. Affron® was administered both through the oral and the intraperitoneal routes, and several tasks related to anxiety and depression, such as the elevated plus maze, the forced swimming test or the sucrose preference test, were assessed. These tasks model key features of depressive states and anxious states relating to fear, behavioral despair or anhedonia, the lack of motivation and/or pleasure from everyday activities, respectively. Animals receiving oral affron® displayed behaviors congruent with improvements in their anxious/depressive state, showing the enhanced consumption of a sweet solution, as well as an increase in certain escape responses in the forced swimming test. Our data support a beneficial role for oral saffron in anxious/depressive states.

Alcohol-induced cognitive deficits are associated with decreased circulating levels of the neurotrophin BDNF in humans and rats.

Chronic alcohol consumption is associated with neurocognitive and memory deficits, dramatically affecting plasticity and connectivity, with maximal expression as dementia. Neurotrophic factors may contribute to alcohol-related cognitive decline. For further investigation, a cross-sectional study was performed to evaluate the association of cognitive impairment, by using frontal assessment battery, and memory loss, using memory failures everyday, with the circulating levels of the neurotrophin brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3) in abstinent subjects with alcohol use disorders (AUDs, N = 58, average of 17.9 years of problematic use and 4.3 months of abstinence) compared with healthy control subjects (N = 22). This association was also explored in a pre-clinical model of adolescent rats chronically exposed to alcohol up to adulthood (~77 days old) in a three-bottle free-choice (5-10-20 percent), repeated abstinence and relapse paradigm. AUD subjects had low educational level and cognitive impairment associated with teenage consumption and lower circulating levels of BDNF and NT-3. Only BDNF concentration showed a positive correlation with frontal assessment battery in AUD patients. In the ethanol-exposed rats, the plasma levels of BDNF and NT-3 were also decreased, and a negative correlation between hippocampal Bdnf mRNA levels and recognition memory was found. The ethanol-exposed rat hippocampus showed a decrease in the mRNA levels of neurotrophic (Bdnf and Ntf-3) and neurogenic (Mki67, Sox2, Dcx, Ncam1 and Calb1) factors, associated to a deactivation of the neurogenic regulator mitogen-activated protein kinase extracellular signal-regulated kinase. Results suggest a relevant role of BDNF/extracellular signal-regulated kinase 2 signaling in alcohol-induced cognitive impairment and suggest that early alcohol exposure-derived effects on cognition are associated with neurotrophin signaling deficits.

Sex-Dimorphic Behavioral Alterations and Altered Neurogenesis in U12 Intron Splicing-Defective Zrsr1 Mutant Mice.

Mutant mice with respect to the splicing factor Zrsr1 present altered spermatogenesis and infertility. To investigate whether Zrsr1 is involved in the homeostatic control that the hypothalamus exerts over reproductive functions, we first analyzed both differential gene and isoform expression and alternative splicing alterations in Zrsr1 mutant (Zrsr1mu) hypothalamus; second, we analyzed the spontaneous and social behavior of Zrsr1mu mice; and third, we analyzed adult cell proliferation and survival in the Zrsr1mu hypothalamus. The Zrsr1mu hypothalamus showed altered expression of genes and isoforms related to the glutathione metabolic process, synaptonemal complex assembly, mRNA transport, and altered splicing events involving the enrichment of U12-type intron retention (IR). Furthermore, increased IR in U12-containing genes related with the prolactin, progesterone, and gonadotropin-releasing hormone (GnRH) reproductive signaling pathway was observed. This was associated with a hyperactive phenotype in both males and females, with an anxious phenotype in females, and with increased social interaction in males, instead of the classical aggressive behavior. In addition, Zrsr1mu females but not males exhibited reduced cell proliferation in both the hypothalamus and the subventricular zone. Overall, these results suggest that Zrsr1 expression and function are relevant to organization of the hypothalamic cell network controlling behavior.

Increased plasma oleoylethanolamide and palmitoleoylethanolamide levels correlate with inflammatory changes in alcohol binge drinkers: the case of HMGB1 in women.

Alcohol binge drinking is a heavy pattern of alcohol consumption increasingly used by young people. In a previous study, we reported that young drinkers with a 2-year history of binge alcohol consumption had an overactivation of the innate immune system and peripheral inflammation when compared with controls. In the present study, we measured several biolipids that are fatty acid derivatives belonging to the acylethanolamide or 2-acylglycerol families in the plasma of the same subjects (n = 42; 20 men and 22 women). We found that during abstinence, alcohol binge drinkers had elevated plasma levels of oleoylethanolamide, palmitoleoylethanolamide, arachidonoylethanolamide, dihomo-γ-linolenoyl ethanolamide and linoleoyl ethanolamide, which positively correlated with changes in the mRNA expression of key inflammatory markers in peripheral blood mononuclear cells, such as toll-like receptors (TLR4), pro-inflammatory cytokines/chemokines interleukin-1 beta, interleukin-6 and monocyte chemoattractant protein-1, and cyclooxygenase-2. Additionally, plasma oleoylethanolamide positively correlated with plasma levels of high mobility group box-1, which is a danger-associated molecular pattern and an endogenous TLR4 agonist, specifically in female alcohol binge drinkers. No changes were observed in 2-acylglycerols in alcohol binge drinkers, although sex-related differences in these bioactive lipids as well as in palmitoleoylethanolamide and docosatetraenoylethanolamide levels were detected. These results extend the previous clinical findings observed in patients diagnosed with long-term alcohol use disorder to young users and suggest a prominent role for these lipids in the response to acute alcohol exposure.

Oleoylethanolamide prevents neuroimmune HMGB1/TLR4/NF-kB danger signaling in rat frontal cortex and depressive-like behavior induced by ethanol binge administration.

Alcohol abuse is frequently characterized by a specific pattern of intake in binge drinking episodes, inducing neuroinflammation and brain damage. Here, we characterized the temporal profile of neuroinflammation in rats exposed to intragastric binge ethanol administrations (3 times/day × 4 days) and tested the anti-inflammatory/neuroprotective properties of the satiety factor oleoylethanolamide (OEA). Pre-treatment with OEA (5 mg/kg, i.p.) previous each alcohol gavage blocked the expression of high mobility group box 1 (HMGB1) danger signal and the innate immunity Toll-like receptors 4 (TLR4) in frontal cortex, and inhibited the nuclear factor-kappa B (NF-kB) proinflammatory cascade induced by alcohol binge administration. OEA reduced the levels of interleukin-1beta (IL-1ß), the monocyte chemoattractant protein-1 (MCP-1), and the enzymes cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in ethanol binged animals. Elevations in plasma tumor necrosis factor alpha (TNF-α) and IL-1ß after ethanol were also inhibited by OEA. OEA also prevented ethanol-induced lipid peroxidation, caspase-8 and pro-apoptotic caspase-3 activation in frontal cortex. Additionally, OEA blocked the rise in blood corticosterone levels after ethanol with no alteration in blood ethanol levels and may affect ethanol-induced gut permeability for endotoxin. Finally, OEA, administered as a pre-treatment during the ethanol binge, exerted antidepressant-like effects during acute withdrawal. Altogether, results highlight a beneficial profile of OEA as a potent anti-inflammatory, antioxidant, neuroprotective and antidepressant-like compound to treat alcohol abuse.

Role of the satiety factor oleoylethanolamide in alcoholism.

Oleoylethanolamide (OEA) is a satiety factor that controls motivational responses to dietary fat. Here we show that alcohol administration causes the release of OEA in rodents, which in turn reduces alcohol consumption by engaging peroxisome proliferator-activated receptor-alpha (PPAR-α). This effect appears to rely on peripheral signaling mechanisms as alcohol self-administration is unaltered by intracerebral PPAR-α agonist administration, and the lesion of sensory afferent fibers (by capsaicin) abrogates the effect of systemically administered OEA on alcohol intake. Additionally, OEA is shown to block cue-induced reinstatement of alcohol-seeking behavior (an animal model of relapse) and reduce the severity of somatic withdrawal symptoms in alcohol-dependent animals. Collectively, these findings demonstrate a homeostatic role for OEA signaling in the behavioral effects of alcohol exposure and highlight OEA as a novel therapeutic target for alcohol use disorders and alcoholism.

Effects of synchronous and asynchronous embryo transfer on postnatal development, adult health, and behavior in mice.

Asynchronous embryo transfer (ET) is a common assisted reproduction technique used in several species, but its biological effects on postnatal and early development remain unknown. The aim of this study was to determine whether asynchronous ET produces long-term effects in mice. Postnatal development, animal weight, systolic blood pressure (SBP), relative organ weight (liver, spleen, kidneys, heart, lungs, brain, and testicles), and behavior (assessed in open-field and elevated plus maze tests) were assessed in CD1 mice produced by different ET procedures: 1) the transfer of Day 3.5 (D3.5) blastocysts to the uterus (BL-UT); 2) the transfer of D3.5 blastocysts to the oviduct (BL-OV); or 3) the transfer of D0.5 zygotes to the oviduct (Z-OV). In vivo conceived animals served as controls (CT). The transfer of blastocysts to the uterus or zygotes to the oviduct was defined as synchronous, and transfer of blastocysts to the oviduct was defined as asynchronous. Both synchronous and asynchronous ET resulted in increased weight at birth that normalized thereafter with the exception of asynchronous ET females. In this group, female BL-OV, a clear lower body weight was recorded along postnatal life when compared with controls (P < 0.05). No effects on animal weight were produced during postnatal development in the synchronous ET groups (BL-UT, Z-OV, and CT). Both synchronous and asynchronous ET had impacts on adult (Wk 30) organ weight. SBP was modified in animals derived from blastocyst but not zygote ET. Effects on behavior (anxiety in the plus maze) were only detected in the BL-UT group (P < 0.05). Our findings indicate that zygotes are less sensitive than blastocysts to ET and that both synchronous and asynchronous blastocyst ET may have long-term consequences on health, with possible impacts on weight, arterial pressure, relative organ weight, and behavior.

Hyperplastic obesity and liver steatosis as long-term consequences of suboptimal in vitro culture of mouse embryos.

In the present study, we identify and describe an obese phenotype in mice as a long-term consequence of a suboptimal in vitro culture that resulted from the addition of fetal calf serum (FCS) into the culture medium. Mice produced with FCS displayed a high mortality rate (approximately 55% versus 15% in control mice within 20 mo) and increased sensitivity to the development of obesity in adulthood when fed either a standard or a high-fat diet. These mice developed hyperplastic obesity that was characterized by a significant expansion of the fat pads (approximately 25% and 32% higher body weight in male and female mice over controls, respectively) with unchanged adipocyte size. We observed a sexual dimorphism in the development of obesity in the mice produced with FCS. Whereas the female mice displayed hypertension, hyperleptinemia, and fatty liver, the male mice only displayed glucose intolerance. The mRNA expression of metabolically relevant genes in the adipose tissue was also affected. The males produced with FCS expressed higher mRNA levels of the genes that activate fatty acid oxidation (peroxisome proliferator-activated receptor alpha [Ppara, PPARalpha] and acyl-CoA oxidase 1 [Acox1, ACOX1]) and thermogenesis (uncoupling protein 1 [Ucp1, UCP1]), which may counteract the metabolic phenotype. Conversely, the females produced with FCS generally expressed lower levels of these metabolic genes. In the females, the obese phenotype was associated with inhibition of the lipogenic pathway (peroxisome proliferator-activated receptor gamma [Pparg, PPARgamma] and fatty acid synthase [Fasn, FAS]), indicating a saturation of the storage capacity of the adipose tissue. Overall, our data indicate that the exposure to suboptimal in vitro culture conditions can lead to the sexually dimorphic development of obesity in adulthood.

Systemic administration of oleoylethanolamide protects from neuroinflammation and anhedonia induced by LPS in rats.

BACKGROUND: The acylethanolamides oleoylethanolamide and palmitoylethanolamide are endogenous lipid mediators with proposed neuroprotectant properties in central nervous system (CNS) pathologies. The precise mechanisms remain partly unknown, but growing evidence suggests an antiinflammatory/antioxidant profile. METHODS: We tested whether oleoylethanolamide/palmitoylethanolamide (10 mg/kg, i.p.) attenuate neuroinflammation and acute phase responses (hypothalamus-pituitary-adrenal (HPA) stress axis stress axis activation, thermoregulation, and anhedonia) induced by lipopolysaccharide (0.5 mg/kg, i.p.) in rats. RESULTS: Lipopolysaccharide increased mRNA levels of the proinflammatory cytokines tumor necrosis factor-α, interleukin-1ß, and interleukin-6, nuclear transcription factor-κB activity, and the expression of its inhibitory protein IκBα in cytoplasm, the inducible isoforms of nitric oxide synthase and cyclooxygenase-2, microsomal prostaglandin E2 synthase mRNA, and proinflammatory prostaglandin E2 content in frontal cortex 150 minutes after administration. As a result, the markers of nitrosative/oxidative stress nitrites (NO2(-)) and malondialdehyde were increased. Pretreatment with oleoylethanolamide/ palmitoylethanolamide reduced plasma tumor necrosis factor-α levels after lipopolysaccharide, but only oleoylethanolamide significantly reduced brain tumor necrosis factor-α mRNA. Oleoylethanolamide and palmitoylethanolamide prevented lipopolysaccharide-induced nuclear transcription factor-κB (NF-κB)/IκBα upregulation in nuclear and cytosolic extracts, respectively, the expression of inducible isoforms of nitric oxide synthase, cyclooxygenase-2, and microsomal prostaglandin E2 synthase and the levels of prostaglandin E2. Additionally, both acylethanolamides reduced lipopolysaccharide-induced oxidative/nitrosative stress. Neither oleoylethanolamide nor palmitoylethanolamide modified plasma corticosterone levels after lipopolysaccharide, but both acylethanolamides reduced the expression of hypothalamic markers of thermoregulation interleukin-1ß, cyclooxygenase-2, and prostaglandin E2, and potentiated the hypothermic response after lipopolysaccharide. Interestingly, only oleoylethanolamide disrupted lipopolysaccharide-induced anhedonia in a saccharine preference test. CONCLUSIONS: Results indicate that oleoylethanolamide and palmitoylethanolamide have antiinflammatory/neuroprotective properties and suggest a role for these acylethanolamides as modulators of CNS pathologies with a neuroinflammatory component.

The administration of atomoxetine during alcohol deprivation induces a time-limited increase in alcohol consumption after relapse.

The administration of selective serotonin reuptake inhibitors (SSRIs) typically used as antidepressants increases alcohol consumption after an alcohol deprivation period in rats. However, the appearance of this effect after the treatment with selective noradrenaline reuptake inhibitors (SNRIs) has not been studied. In the present work we examined the effects of a 15-d treatment with the SNRI atomoxetine (1, 3 and 10 mg/kg, i.p.) in male rats trained to drink alcohol solutions in a 4-bottle choice test. The treatment with atomoxetine (10 mg/kg, i.p.) during an alcohol deprivation period increased alcohol consumption after relapse. This effect only lasted one week, disappearing thereafter. Treatment with atomoxetine did not cause a behavioral sensitized response to a challenge dose of amphetamine (1.5 mg/kg, i.p.), indicating the absence of a supersensitive dopaminergic transmission. This effect is markedly different from that of SSRI antidepressants that produced both long-lasting increases in alcohol consumption and behavioral sensitization. Clinical implications are discussed.

Cocaine-induced behavioral sensitization is associated with changes in the expression of endocannabinoid and glutamatergic signaling systems in the mouse prefrontal cortex.

BACKGROUND: Endocannabinoids modulate the glutamatergic excitatory transmission by acting as retrograde messengers. A growing body of studies has reported that both signaling systems in the mesocorticolimbic neural circuitry are involved in the neurobiological mechanisms underlying drug addiction. METHODS: We investigated whether the expression of both endocannabinoid and glutamatergic systems in the prefrontal cortex (PFC) were altered by an acute and/or repeated cocaine administration schedule that resulted in behavioral sensitization. We measured the protein and mRNA expression of the main endocannabinoid metabolic enzymes and the cannabinoid receptor type 1 (CB1). We also analyzed the mRNA expression of relevant components of the glutamate-signaling system, including glutamate-synthesizing enzymes, metabotropic receptors, and ionotropic receptors. RESULTS: Although acute cocaine (10 mg/kg) produced no significant changes in the endocannabinoid-related proteins, repeated cocaine administration (20 mg/kg daily) induced a pronounced increase in the CB1 receptor expression. In addition, acute cocaine administration (10 mg/kg) in cocaine-sensitized mice (referred to as cocaine priming) induced a selective increase in the endocannabinoid-degrading enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL). These protein changes were accompanied by an overall decrease in the ratios of endocannabinoid synthesis/degradation, especially the N-acyl phosphatidylethanolamine phospholipase D/FAAH and diacylglycerol lipase alpha/MAGL ratios. Regarding mRNA expression, while acute cocaine administration produced a decrease in CB1 receptors and N-acyl phosphatidylethanolamine phospholipase D, repeated cocaine treatment enhanced CB1 receptor expression. Cocaine-sensitized mice that were administered priming injections of cocaine mainly displayed an increased FAAH expression. These endocannabinoid changes were associated with modifications in glutamatergic transmission-related genes. An overall decrease was observed in the mRNA expression of the glutamate-synthesizing gene kidney-type glutaminase (KGA), the metabotropic glutamate receptors (mGluR3 and GluR), and subunits of NMDA ionotropic receptors (NR1, NR2A, NR2B and NR2C) after acute cocaine administration, while mice repeatedly exposed to cocaine only displayed an increase in NR2C. However, in cocaine-sensitized mice primed with cocaine, this inhibition was reversed and a strong increase was detected in the mGluR5, NR2 subunits, and both GluR1 and GluR3. CONCLUSIONS: These findings indicate that cocaine sensitization is associated with an endocannabinoid downregulation and a hyperglutamatergic state in the PFC that, overall, contribute to an enhanced glutamatergic input into PFC-projecting areas.

Increased alcohol consumption in rats after subchronic antidepressant treatment.

The use of antidepressants for alcoholism in humans has been a matter of controversy in recent years. Despite the existence of an important co-morbidity for depression and alcoholism, some studies suggest that the use of antidepressants could worsen the prognosis of alcoholism. However, there is a lack of studies in animal models exploring this phenomenon. In the present study, we show how the 15-d treatment with fluoxetine (10 mg/kg) or venlafaxine (50 mg/kg) affected alcohol deprivation effect (ADE) and subsequent alcohol consumption. Initially, fluoxetine reduced ADE and venlafaxine did not affect it. However, in the following days, both antidepressants increased alcohol consumption, an effect that was found to last at least 5 wk. Fluoxetine treatment was shown to cause a locomotor sensitized response to a challenge dose of amphetamine (0.5 mg/kg), indicating the presence of a supersensitive dopaminergic transmission. In summary, antidepressant treatment may increase alcohol consumption in rats after a period of alcohol deprivation and this could be related to alterations in the reward circuitry. This finding confirms in an animal model previous reports in humans that may limit the use of antidepressants for alcoholism.

Involvement of the ghrelin system in the maintenance and reinstatement of cocaine-motivated behaviors: a role of adrenergic action at peripheral ß1 receptors.

Cocaine addiction is a significant medical and public concern. Despite decades of research effort, development of pharmacotherapy for cocaine use disorder remains largely unsuccessful. This may be partially due to insufficient understanding of the complex biological mechanisms involved in the pathophysiology of this disorder. In the present study, we show that: (1) elevation of ghrelin by cocaine plays a critical role in maintenance of cocaine self-administration and cocaine-seeking motivated by cocaine-conditioned stimuli; (2) acquisition of cocaine-taking behavior is associated with the acquisition of stimulatory effects of cocaine by cocaine-conditioned stimuli on ghrelin secretion, and with an upregulation of ghrelin receptor mRNA levels in the ventral tegmental area (VTA); (3) blockade of ghrelin signaling by pretreatment with JMV2959, a selective ghrelin receptor antagonist, dose-dependently inhibits reinstatement of cocaine-seeking triggered by either cocaine or yohimbine in behaviorally extinguished animals with a history of cocaine self-administration; (4) JMV2959 pretreatment also inhibits brain stimulation reward (BSR) and cocaine-potentiated BSR maintained by optogenetic stimulation of VTA dopamine neurons in DAT-Cre mice; (5) blockade of peripheral adrenergic ß1 receptors by atenolol potently attenuates the elevation in circulating ghrelin induced by cocaine and inhibits cocaine self-administration and cocaine reinstatement triggered by cocaine. These findings demonstrate that the endogenous ghrelin system plays an important role in cocaine-related addictive behaviors and suggest that manipulating and targeting this system may be viable for mitigating cocaine use disorder.

Discovery of V-0219: A Small-Molecule Positive Allosteric Modulator of the Glucagon-Like Peptide-1 Receptor toward Oral Treatment for "Diabesity".

Peptidic agonists of the glucagon-like peptide-1 receptor (GLP-1R) have gained a prominent role in the therapy of type-2 diabetes and are being considered for reducing food intake in obesity. Potential advantages of small molecules acting as positive allosteric modulators (PAMs) of GLP-1R, including oral administration and reduced unwanted effects, could improve the utility of this class of drugs. Here, we describe the discovery of compound 9 (4-{[1-({3-[4-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}methyl)piperidin-3-yl]methyl}morpholine, V-0219) that exhibits enhanced efficacy of GLP-1R stimulation, subnanomolar potency in the potentiation of insulin secretion, and no significant off-target activities. The identified GLP-1R PAM shows a remarkable in vivo activity, reducing food intake and improving glucose handling in normal and diabetic rodents. Enantioselective synthesis revealed oral efficacy for (S)-9 in animal models. Compound 9 behavior bolsters the interest of a small-molecule PAM of GLP-1R as a promising therapeutic approach for the increasingly prevalent obesity-associated diabetes.

Cerebellar and cortical TLR4 activation and behavioral impairments in Wernicke-Korsakoff Syndrome: Pharmacological effects of oleoylethanolamide.

Wernicke-Korsakoff Syndrome (WKS) is a neuropsychiatric disorder whose etiology is a thiamine deficiency (TD), with alcoholism being the main underlying cause. Previous evidence suggests the presence of initial neuroinflammation and oxidative/nitrosative stress in the physiopathology, although the specific molecular mechanisms underlying TD-induced brain damage and behavioral disabilities are unknown. We explored the specific role of the innate immune receptor TLR4 in three murine models of WKS, based on the combination of a thiamine-deficient diet and pyrithiamine injections (0.25 mg/kg, i.p.) over time. The Symptomatic Model (SM) allowed us to describe the complete neurological/neurobehavioral symptomatology over 16 days of TD. Animals showed an upregulation of the TLR4 signaling pathway both in the frontal cortex (FC) and cerebellum and clear motor impairments related with cerebellar dysfunction. However, in the Pre-Symptomatic Model (PSM), 12 days of TD induced the TLR4 pathway upregulation in the FC, which correlated with disinhibited-like behavior, but not in the cerebellum, and no motor impairments. In addition, we tested the effects of the biolipid oleoylethanolamide (OEA, 10 mg/kg, i.p., once daily, starting before any symptom of the pathology is manifested) through the Glucose-Precipitated Model (GPM), which was generated by glucose loading (5 g/kg, i.v., last day) in thiamine-deficient animals to accelerate damage. Pretreatment with OEA prevented the TLR4-induced signature in the FC, as well as an underlying incipient memory disability and disinhibited-like behavior. This study suggests a key role for TLR4 in TD-induced neuroinflammation in the FC and cerebellum, and it reveals different vulnerability of these brain regions in WKS over time. Pre-treatment with OEA counteracts TD-induced TLR4-associated neuroinflammation and may serve as co-adjuvant therapy to prevent WKS-induced neurobehavioral alterations.

Sex-specific behavioral and neurogenic responses to cocaine in mice lacking and blocking dopamine D1 or dopamine D2 receptors.

Adult neurogenesis in rodents is modulated by dopaminergic signaling and inhibited by cocaine. However, the sex-specific role of dopamine D1 and D2 receptors (D1R, D2R) in the deleterious effect of cocaine on adult neurogenesis has not been described yet. Here, we explored sex differences in (a) cell proliferation (5'-bromo-2'-deoxyuridine [BrdU]), (b) neural precursor (nestin), (c) neuronal phenotype (BrdU/ß3-tubulin), and (d) neuronal maturity (NeuN) in the subventricular zone (SVZ) of the lateral ventricles and striatum of mice with genetic deletion (D1-/- , D2-/- ) or pharmacological blockage (SCH23390: 0.1 mg/kg/day/5 days; Raclopride: 0.3 mg/kg/day/5 days) of D1R and D2R, and treated (10 mg/kg/day/5 days) and then challenged (5 mg/kg, 48 hr later) with cocaine. Results indicated that hyperactivity responses to cocaine were absent in D1-/- mice and reduced in SCH23390-treated mice. Activity responses to cocaine were reduced in D2-/- males, but absent in D2-/- females and increased in Raclopride-treated females. D1R deletion blocked the deleterious effect of cocaine on SVZ cell proliferation in males. Cocaine-exposed D1-/- males also had reduced neuronal phenotype of SVZ newborn cells and increased striatal neuronal maturity. D2-/- mice had lower proliferative and neural precursor responses. Cocaine in D2-/- females or coadministered with Raclopride in wild-type females improved SVZ cell proliferation, an effect that positively correlated with plasma brain-derived neurotrophic factor (BDNF) concentrations. In conclusion, the sex-specific D1R and D2R signaling on SVZ cell proliferation, neural progenitor and neuronal maturity is differentially perturbed by cocaine, and BDNF may be required to link D2R to neuroplasticity in cocaine addiction in females.

Sudden cessation of fluoxetine before alcohol drinking reinstatement alters microglial morphology and TLR4/inflammatory neuroadaptation in the rat brain.

Preclinical studies on the effects of abrupt cessation of selective serotonin reuptake inhibitors (SSRIs), a medication often prescribed in alcohol use disorder (AUD) patients with depression, results in alcohol consumption escalation after resuming drinking. However, a potential neuroinflammatory component on this escalation remains unexplored despite the immunomodulatory role of serotonin. Here, we utilized a rat model of 14-daily administration of the SSRI fluoxetine (10 mg/kg/day) along alcohol self-administration deprivation to study the effects of fluoxetine cessation on neuroinflammation after resuming alcohol drinking. Microglial morphology and inflammatory gene expression were analyzed in prelimbic cortex, striatum, basolateral amygdala and dorsal hippocampus. Results indicated that alcohol drinking reinstatement increased microglial IBA1 immunoreactivity and altered morphometric features of activated microglia (fractal dimension, lacunarity, density, roughness, and cell area, perimeter and circularity). Despite alcohol reinstatement, fluoxetine cessation modified microglial morphology in a brain region-specific manner, resulting in hyper-ramified (spatial complexity of branching), reactive (lower heterogeneity and circularity)-like microglia. We also found that microglial cell area correlated with changes in mRNA expression of chemokines (Cx3cl1/fractalkine, Cxcl12/SDF1α, Ccl2/MCP1), cytokines (IL1ß, IL6, IL10) and the innate immune toll-like receptor 4 (TLR4) in dorsal hippocampus. Specifically, TLR4 correlated with microglial spatial complexity assessed by fractal dimension in striatum, suggesting a role in process branching. These findings suggest that alcohol drinking reinstatement after fluoxetine treatment cessation disturbs microglial morphology and reactive phenotype associated with a TLR4/inflammatory response to alcohol in a brain region-specific manner, facts that might contribute to alcohol-induced damage through the promotion of escalation of alcohol drinking behavior.