Happyhour, a Ste20 family kinase, implicates EGFR signaling in ethanol-induced behaviors.

The consequences of alcohol use disorders (AUDs) are devastating to individuals and society, yet few treatments are currently available. To identify genes regulating the behavioral effects of ethanol, we conducted a genetic screen in Drosophila and identified a mutant, happyhour (hppy), due to its increased resistance to the sedative effects of ethanol. Hppy protein shows strong homology to mammalian Ste20 family kinases of the GCK-1 subfamily. Genetic and biochemical experiments revealed that the epidermal growth factor (EGF)-signaling pathway regulates ethanol sensitivity in Drosophila and that Hppy functions as an inhibitor of the pathway. Acute pharmacological inhibition of the EGF receptor (EGFR) in adult animals altered acute ethanol sensitivity in both flies and mice and reduced ethanol consumption in a preclinical rat model of alcoholism. Inhibitors of the EGFR or components of its signaling pathway are thus potential pharmacotherapies for AUDs.

Neural serotonergic circuits for controlling long-term voluntary alcohol consumption in mice.

Alcohol-use-disorders are chronic relapsing illnesses, often co-morbid with anxiety. We have previously shown using the "drinking-in-the-dark" model in mice that the stimulation of the serotonin receptor 1A (5-HT1A) reduces ethanol binge-drinking behaviour and withdrawal-induced anxiety. The 5-HT1A receptor is located either on Raphe neurons as autoreceptors, or on target neurons as heteroreceptors. By combining a pharmacological approach with biased agonists targeting the 5-HT1A auto- or heteroreceptor and a chemogenetic approach (DREADDs), here we identified that ethanol-binge drinking behaviour is dependent on 5-HT1A autoreceptors and 5-HT neuronal function, with a transition from DRN-dependent regulation of short-term (6 weeks) ethanol intake, to MRN-dependent regulation after longer ethanol exposure (12 weeks). We further identified a serotonergic microcircuit (5-HTMRN→DG) originating from the MRN and projecting to the dentate gyrus (DG) of the hippocampus, that is specifically affected by, and modulates long-term ethanol consumption. The present study indicates that targeting Raphe nuclei 5-HT1A autoreceptors with agonists might represent an innovative pharmacotherapeutic strategy to combat alcohol abuse.

Retrieval of olfactory fear memory alters cell proliferation and expression of pCREB and pMAPK in the corticomedial amygdala and piriform cortex.

The brain forms robust associations between odors and emotionally salient memories, making odors especially effective at triggering fearful or traumatic memories. Using Pavlovian olfactory fear conditioning (OFC), a variant of the traditional tone-shock paradigm, this study explored the changes involved in its processing. We assessed the expression of neuronal plasticity markers phosphorylated cyclic adenosine monophosphate response element binding protein (pCREB) and phosphorylated mitogen-activated protein kinase (pMAPK) 24 h and 14 days following OFC, in newborn neurons (EdU+) and in brain regions associated with olfactory memory processing; the olfactory bulb, piriform cortex, amygdale, and hippocampus. Here, we show that all proliferating neurons in the dentate gyrus of the hippocampus and glomerular layer of the olfactory bulb were colocalized with pCREB at 24 h and 14 days post-conditioning, and the number of proliferating neurons at both time points were statistically similar. This suggests the occurrence of long-term potentiation within the neurons of this pathway. Finally, OFC significantly increased the density of pCREB- and pMAPK-positive immunoreactive neurons in the medial and cortical subnuclei of the amygdala and the posterior piriform cortex, suggesting their key involvement in its processing. Together, our investigation identifies changes in neuroplasticity within critical neural circuits responsible for olfactory fear memory.

Modulation of serotonin and noradrenaline in the BLA by pindolol reduces long-term ethanol intake.

Repeated cycles of binge-like alcohol consumption and abstinence change the activity of several neurotransmitter systems. Some of these changes are consolidated following prolonged alcohol use and are thought to play an important role in the development of dependence. We have previously shown that systemic administration of the dual beta-adrenergic antagonist and 5-HT1A/1B partial agonist pindolol selectively reduces long-term but not short-term binge-like consumption of ethanol and alters excitatory postsynaptic currents in basolateral amygdala (BLA) principal neurons. The aim of this study was to investigate the effects of pindolol microinfusions in the BLA on long-term ethanol intake using the drinking-in-the-dark paradigm in mice. We also microinfused RU24969 (5-HT1A/1B receptor partial agonist) and CGP12177 (ß1/2 adrenergic antagonist) following long-term ethanol intake and determined the densities of 5-HT1A/1B receptors and ß1/2 adrenergic in the BLA following short-term (4 weeks) and long-term ethanol (12 weeks) consumption. We show that intra-BLA infusion of pindolol (1000 pmol/0.5 µl), RU24969 (0.3 and 3 pmol/0.5 µl) and CGP12177 (500 pmol/0.5 µl) produce robust decreases in long-term ethanol consumption. Additionally, we identified reduced ß1/2 adrenergic receptor expression and no change in 5-HT1A/1B receptor density in the BLA of long-term ethanol-consuming mice. Collectively, our data highlight the effects of pindolol on voluntary, binge-like ethanol consumption behavior following long-term intake.

The antihypertensive drug pindolol attenuates long-term but not short-term binge-like ethanol consumption in mice.

Alcohol dependence is a debilitating disorder with current therapies displaying limited efficacy and/or compliance. Consequently, there is a critical need for improved pharmacotherapeutic strategies to manage alcohol use disorders (AUDs). Previous studies have shown that the development of alcohol dependence involves repeated cycles of binge-like ethanol intake and abstinence. Therefore, we used a model of binge-ethanol consumption (drinking-in-the-dark) in mice to test the effects of compounds known to modify the activity of neurotransmitters implicated in alcohol addiction. From this, we have identified the FDA-approved antihypertensive drug pindolol, as a potential candidate for the management of AUDs. We show that the efficacy of pindolol to reduce ethanol consumption is enhanced following long-term (12 weeks) binge-ethanol intake, compared with short-term (4 weeks) intake. Furthermore, pindolol had no effect on locomotor activity or consumption of the natural reward sucrose. Because pindolol acts as a dual beta-adrenergic antagonist and 5-HT1A/1B partial agonist, we examined its effect on spontaneous synaptic activity in the basolateral amygdala (BLA), a brain region densely innervated by serotonin and norepinephrine-containing fibres. Pindolol increased spontaneous excitatory post-synaptic current frequency of BLA principal neurons from long-term ethanol-consuming mice but not naïve mice. Additionally, this effect was blocked by the 5-HT1A/1B receptor antagonist methiothepin, suggesting that altered serotonergic activity in the BLA may contribute to the efficacy of pindolol to reduce ethanol intake following long-term exposure. Although further mechanistic investigations are required, this study demonstrates the potential of pindolol as a new treatment option for AUDs that can be fast-tracked into human clinical studies.

Alcohol and nicotine interactions: pre-clinical models of dependence.

While the co-morbidity of alcohol (ethanol) and tobacco (nicotine) dependence is well described, the processes that underpin this strong connection are still under debate. With the increasing popularity of electronic cigarettes (e-cigarettes), it is now becoming more important to look to the neurobiological mechanisms involving alcohol and nicotine interactions to effectively treat a new generation of co-dependent individuals. Researchers have already recognized that the neuropathology produced by the combination of nicotine and ethanol is likely to produce an addictive nature very different to that of either one alone, and are employing a mixture of pre-clinical techniques to establish and investigate every stage in the development of both nicotine and ethanol-seeking behaviors. While it is agreed that multiple pathways orchestrate the complex reward profile of alcohol and nicotine co-addiction, several lines of evidence suggest the convergent site of action is within the mesolimbic dopaminergic system, at neuronal nicotinic acetylcholine receptors (nAChRs). A whole host of strategies are currently being employed to discover and unravel previously unknown or ill understood neurobiological processes in the brain, contributing greatly toward the development of novel pharmacotherapies with the aim of improving patient outcomes. This review intends to shed some light on the most influential and most recent pre-clinical work that is leading the charge in modeling this complicated relationship.

Structural and functional characterization of dendritic arbors and GABAergic synaptic inputs on interneurons and principal cells in the rat basolateral amygdala.

The basolateral amygdala (BLA) is a complex brain region associated with processing emotional states, such as fear, anxiety, and stress. Some aspects of these emotional states are driven by the network activity of synaptic connections, derived from both local circuitry and projections to the BLA from other regions. Although the synaptic physiology and general morphological characteristics are known for many individual cell types within the BLA, the combination of morphological, electrophysiological, and distribution of neurochemical GABAergic synapses in a three-dimensional neuronal arbor has not been reported for single neurons from this region. The aim of this study was to assess differences in morphological characteristics of BLA principal cells and interneurons, quantify the distribution of GABAergic neurochemical synapses within the entire neuronal arbor of each cell type, and determine whether GABAergic synaptic density correlates with electrophysiological recordings of inhibitory postsynaptic currents. We show that BLA principal neurons form complex dendritic arborizations, with proximal dendrites having fewer spines but higher densities of neurochemical GABAergic synapses compared with distal dendrites. Furthermore, we found that BLA interneurons exhibited reduced dendritic arbor lengths and spine densities but had significantly higher densities of putative GABAergic synapses compared with principal cells, which was correlated with an increased frequency of spontaneous inhibitory postsynaptic currents. The quantification of GABAergic connectivity, in combination with morphological and electrophysiological measurements of the BLA cell types, is the first step toward a greater understanding of how fear and stress lead to changes in morphology, local connectivity, and/or synaptic reorganization of the BLA.

Intermittent access ethanol consumption dysregulates CRF function in the hypothalamus and is attenuated by the CRF-R1 antagonist, CP-376395.

Corticotrophin-releasing factor (CRF) is a mediator of stress responses and a key modulator of ethanol-mediated behaviors. We report here that the CRF receptor 1 (CRF-R1) antagonist, CP-376395 reduces 20% ethanol consumption in animals trained to consume ethanol on an intermittent, but not a continuous, schedule. Furthermore, using [(35) S]GTPγS binding assays, we demonstrate that CRF-mediated G-protein signaling in the hypothalamus of the intermittent drinkers is decreased when compared to controls suggesting that the effects of CP-376395 are mediated by extrahypothalamic mechanisms. The present study provides further support for the use of CRF-R1 antagonists for the treatment of alcohol use disorders and suggests that ethanol consumption dysregulates CRF function in the hypothalamus.

A Systematic Review and Narrative Synthesis of Cognitive Training in the Treatment of Mental Illness and Substance Use Disorder.

Introduction: The one unifying and distinguishing feature of all neuropsychiatric illnesses is the co-occurrence of cognitive dysfunction. Cognitive training (CT) was developed to enhance neural connectivity and cognition and improve day-to-day functioning. However, the benefits of CT are still debated. This current systematic review aimed to examine the efficacy of CT and to identify diagnostic and CT characteristics associated with superior outcomes across a range of psychiatric disorders. Method: Studies investigating CT in psychiatric illnesses were extracted from Embase, PubMed, CINAHL, PsycINFO, and PsycARTICLES up to 17 August 2023. Inclusion criteria were randomised control trials (RCT) and English language. The primary search strategy included terms relating to cognitive training, cognitive remediation, cognitive enhancement, or cognitive rehabilitation and randomised control trials, clinical trials, or experiments. Risk of bias was assessed using RevMan Web version 8.1.1. Narrative synthesis was used to analyse findings. Due to the heterogeneity of participant demographics, diagnoses, and interventions, meta-analyses were considered inappropriate. Results: Fifteen studies, including a total of 1075 participants, were identified. Approximately 67% of studies reported significant improvements in at least one trained domain of cognitive function after CT, and 47% observed improvements in psychiatric symptoms or function. Cognitive transfer effects were not observed. Sample sizes for studies were generally small, and most CT durations were 6 weeks or less. Conclusions: Findings suggest that CT can improve cognitive function in trained domains, though little evidence of cognitive transfer effects was observed. Due to the lack of standardisation in CT format and delivery, and inadequate measures of psychiatric symptoms or daily function, there is insufficient evidence to conclude whether or not this technique may benefit cognitive impairment in psychiatric disorders, or lead to subsequent improvement in disease symptomatology. Further studies of longer duration and using consistent methodologies must be conducted to identify the benefits of CT in psychiatric disorders.

δ-opioid receptor function in the dorsal striatum plays a role in high levels of ethanol consumption in rats.

Binge-like patterns of excessive drinking during young adulthood increase the propensity for alcohol use disorders (AUDs) later in adult life; however, the mechanisms that drive this are not completely understood. Previous studies showed that the δ-opioid peptide receptor (DOP-R) is dynamically regulated by exposure to ethanol and that the DOP-R plays a role in ethanol-mediated behaviors. The aim of this study was to determine the role of the DOP-R in high ethanol consumption from young adulthood through to late adulthood by measuring DOP-R-mediated [(35)S]GTPγS binding in brain membranes and DOP-R-mediated analgesia using a rat model of high ethanol consumption in Long Evans rats. We show that DOP-R activity in the dorsal striatum and DOP-R-mediated analgesia changes during development, being highest during early adulthood and reduced in late adulthood. Intermittent access to ethanol but not continuous ethanol or water from young adulthood leads to an increase in DOP-R activity in the dorsal striatum and DOP-R-mediated analgesia into late adulthood. Multiple microinfusions of naltrindole into the dorsal striatum or multiple systemic administration of naltrindole reduces ethanol consumption, and following termination of treatment, DOP-R activity in the dorsal striatum is attenuated. These findings suggest that DOP-R activity in the dorsal striatum plays a role in high levels of ethanol consumption and suggest that targeting the DOP-R is an alternative strategy for the treatment of AUDs.

The α5 neuronal nicotinic acetylcholine receptor subunit plays an important role in the sedative effects of ethanol but does not modulate consumption in mice.

BACKGROUND: Alcohol use disorders (AUDs) are a major public health problem, and the few treatment options available to those seeking treatment offer only modest success rates. There remains a need to identify novel targets for the treatment of AUDs. The neuronal nicotinic acetylcholine receptors (nAChRs) represent a potential therapeutic target in the brain, as recent human genetic studies have implicated gene variants in the α5 nAChR subunit as high risk factors for developing alcohol dependence. METHODS: Here, we evaluate the role of the α5* nAChR for ethanol (EtOH)-mediated behaviors using male α5+/+ and α5-/- transgenic mice. We characterized the effect of hypnotic doses of EtOH and investigated drinking behavior using an adapted drinking-in-the-dark (DID) paradigm that has been shown to induce high EtOH consumption in mice. RESULTS: We found the α5 subunit to be important in mediating the sedative effects of EtOH. The α5-/- mice showed slower recovery from EtOH-induced sleep, as measured by loss of righting reflex. Additionally, the α5-/- mice showed enhanced impairment to EtOH-induced ataxia. We found the initial sensitivity to EtOH and EtOH metabolism to be similar in both α5+/+ and α5-/- mice. Hence, the enhanced sedation is likely due to a difference in the acute tolerance of EtOH in α5-/- mice. However, the α5 subunit did not play a role in EtOH consumption for EtOH concentrations ranging from 5 to 30% using the DID paradigm. Additionally, varenicline was effective in reducing EtOH intake in α5-/- mice. CONCLUSIONS: Together, our data suggest that the α5 nAChR subunit is important for the sedative effects of EtOH but does not play a role in EtOH consumption in male mice. Varenicline can be a treatment option even when there is loss of function of the α5 nAChR subunit.

The Impact of Free Sugar on Human Health-A Narrative Review.

The importance of nutrition in human health has been understood for over a century. However, debate is ongoing regarding the role of added and free sugars in physiological and neurological health. In this narrative review, we have addressed several key issues around this debate and the major health conditions previously associated with sugar. We aim to determine the current evidence regarding the role of free sugars in human health, specifically obesity, diabetes, cardiovascular diseases, cognition, and mood. We also present some predominant theories on mechanisms of action. The findings suggest a negative effect of excessive added sugar consumption on human health and wellbeing. Specific class and source of carbohydrate appears to greatly influence the impact of these macronutrients on health. Further research into individual effects of carbohydrate forms in diverse populations is needed to understand the complex relationship between sugar and health.

The Impact of Free and Added Sugars on Cognitive Function: A Systematic Review and Meta-Analysis.

A relationship between excessive sugar consumption and cognitive function has been described in animal models, but the specific effects of sugars in humans remains unclear. This systematic review and meta-analysis aimed to evaluate the current knowledge, research characteristics, and quality of evidence of studies investigating the impacts of free and added sugars on human cognition in healthy participants. The review identified 77 studies (65 experimental trials, n = 3831; 9 cross-sectional studies, n = 11,456; and 3 cohort studies, n = 2059). All cohort studies and eight of the nine cross-sectional studies found significant positive correlations between added sugar consumption and risk of cognitive impairment. Four studies identified reduced risk of cognitive impairment associated with natural fructose-containing foods. The majority of randomised control trials assessed short-term glucose facilitation effects on cognitive outcomes. The results from these studies suggest the need for a tightly regulated blood glucose level, dependent on individualised physiological factors, for optimal cognitive function. A meta-analysis of a subset of studies that assessed the impact of glucose on recall found improvements in immediate free recall compared to controls (p = 0.002). The findings highlight the potentially detrimental effect of excessive, long-term, or prenatal added sugar consumption on cognitive function. Further research is needed to examine the specific effects of free and added sugars on cognitive function.

Evidence for CRHR1 in multiple sclerosis using supervised machine learning and meta-analysis in 12,566 individuals.

The primary genetic risk factor in multiple sclerosis (MS) is the HLA-DRB1*1501 allele; however, much of the remaining genetic contribution to MS has yet to be elucidated. Several lines of evidence support a role for neuroendocrine system involvement in autoimmunity which may, in part, be genetically determined. Here, we comprehensively investigated variation within eight candidate hypothalamic-pituitary-adrenal (HPA) axis genes and susceptibility to MS. A total of 326 SNPs were investigated in a discovery dataset of 1343 MS cases and 1379 healthy controls of European ancestry using a multi-analytical strategy. Random Forests, a supervised machine-learning algorithm, identified eight intronic SNPs within the corticotrophin-releasing hormone receptor 1 or CRHR1 locus on 17q21.31 as important predictors of MS. On the basis of univariate analyses, six CRHR1 variants were associated with decreased risk for disease following a conservative correction for multiple tests. Independent replication was observed for CRHR1 in a large meta-analysis comprising 2624 MS cases and 7220 healthy controls of European ancestry. Results from a combined meta-analysis of all 3967 MS cases and 8599 controls provide strong evidence for the involvement of CRHR1 in MS. The strongest association was observed for rs242936 (OR = 0.82, 95% CI = 0.74-0.90, P = 9.7 × 10(-5)). Replicated CRHR1 variants appear to exist on a single associated haplotype. Further investigation of mechanisms involved in HPA axis regulation and response to stress in MS pathogenesis is warranted.

Ghrelin receptor (GHS-R1A) antagonism suppresses both operant alcohol self-administration and high alcohol consumption in rats.

The mechanisms involved in alcohol use disorders are complex. It has been shown that ghrelin is an important signal for the control of body weight homeostasis, preferably by interacting with hypothalamic circuits, as well as for drug reward by activating the mesolimbic dopamine system. The ghrelin receptor (GHS-R1A) has been shown to be required for alcohol-induced reward. Additionally, ghrelin increases and GHR-R1A antagonists reduce moderate alcohol consumption in mice, and a single nucleotide polymorphism in the GHS-R1A gene has been associated with high alcohol consumption in humans. However, the role of central ghrelin signaling in high alcohol consumption is not known. Therefore, the role of GHS-R1A in operant self-administration of alcohol in rats as well as for high alcohol consumption in Long-Evans rats and in alcohol preferring [Alko alcohol (AA)] rats was studied here. In the present study, the GHS-R1A antagonist, JMV2959, was found to reduce the operant self-administration of alcohol in rats and to decrease high alcohol intake in Long-Evans rats as well as in AA rats. These results suggest that the ghrelin receptor signaling system, specifically GHS-R1A, is required for operant self-administration of alcohol and for high alcohol intake in rats. Therefore, the GHS-R1A may be a therapeutic target for treatment of addictive behaviors, such as alcohol dependence.

The delta opioid receptor antagonist, SoRI-9409, decreases yohimbine stress-induced reinstatement of ethanol-seeking.

A major problem in treating alcohol use disorders (AUDs) is the high rate of relapse due to stress and re-exposure to cues or an environment previously associated with alcohol use. Stressors can induce relapse to alcohol-seeking in humans or reinstatement in rodents. Delta opioid peptide receptors (DOP-Rs) play a role in cue-induced reinstatement of ethanol-seeking; however, their role in stress-induced reinstatement of ethanol-seeking is not known. The objective of this study was to determine the role of DOP-Rs in yohimbine-stress-induced reinstatement of ethanol-seeking. Male, Long-Evans rats were trained to self-administer 10% ethanol in daily 30-minute operant self-administration sessions using a FR3 schedule of reinforcement, followed by extinction training. Once extinction criteria were met, we examined the effects of the DOP-R antagonist, SoRI-9409 (0-5 mg/kg, i.p.) on yohimbine (2 mg/kg, i.p.) stress-induced reinstatement. Additionally, DOP-R-stimulated [(35) S]GTPγS binding was measured in brain membranes and plasma levels of corticosterone (CORT) were determined. Pre-treatment with SoRI-9409 decreased yohimbine stress-induced reinstatement of ethanol-seeking but did not affect yohimbine-induced increases in plasma CORT levels. Additionally, yohimbine increased DOP-R-stimulated (35) [S]GTPγS binding in brain membranes of ethanol-trained rats, an effect that was inhibited by SoRI-9409. This suggests that the DOP-R plays an important role in yohimbine-stress-induced reinstatement of ethanol-seeking behavior, and DOP-R antagonists may be promising candidates for further development as a treatment for AUDs.

Dissecting the contribution of 5-HT1A auto- and heteroreceptors in sucrose overconsumption in mice.

The rise in obesity prevalence has been linked to overconsumption of high-sugar containing food and beverages. Recent evidence suggests that chronic sucrose consumption leads to changes in serotonergic neuroplasticity within the neural circuits involved in feeding control. Although there is a relationship between serotonin signalling in the brain and diet-induced obesity, the specific serotonin (5-HT) receptors or pathways involved remain unknown. The 5-HT1A receptor subtype plays a role in regulating mood, anxiety, and appetite, and has been associated with reversing addiction to substances of abuse. However, the respective role of 5-HT1A auto- vs heteroreceptors in sucrose consumption has not been examined. Mice were given controlled access to either 5%, 10% or 25% w/v sucrose, or water as a control, for 12 weeks using the well-established "drinking in the dark" protocol (n = 6-8 mice per group). Ligands selectively targeting 5-HT1A auto- and/or heteroreceptors (NLX-112, unbiased 5-HT1A receptor agonist; NLX-101, preferential heteroreceptor agonist; F13714, preferential autoreceptor agonist) were administered i.p. acutely after 6 and 12 weeks of sucrose consumption. The specific involvement of 5-HT1A receptors in these effects was verified by blockade with the selective 5-HT1A receptors antagonist WAY-100,635. The specific subpopulation of 5-HT1A receptors involved in sucrose consumption was dependent on the concentration of sucrose solution and the duration of exposure to sucrose (6 weeks vs 12 weeks). Long-term sucrose consumption leads to accentuated 5-HT1A autoreceptor function. Thus, targeting 5-HT1A autoreceptors might represent an effective therapeutic strategy to combat the rise in obesity resulting from the overconsumption of high-sugar diet.

Development and use of a high-throughput screen to identify novel modulators of the corticotropin releasing factor binding protein.

BACKGROUND: Stress responses are believed to involve corticotropin releasing factor (CRF), its two cognate receptors (CRF1 and CRF2), and the CRF-binding protein (CRFBP). Whereas decades of research has focused on CRF1, the role of CRF2 in the central nervous system (CNS) has not been thoroughly investigated. We have previously reported that CRF2, interacting with a C terminal fragment of CRFBP, CRFBP(10kD), may have a role in the modulation of neuronal activity. However, the mechanism by which CRF interacts with CRFBP(10kD) and CRF2 has not been fully elucidated due to the lack of useful chemical tools to probe CRFBP. METHODS: We miniaturized a cell-based assay, where CRFBP(10kD) is fused as a chimera with CRF2, and performed a high-throughput screen (HTS) of 350,000 small molecules to find negative allosteric modulators (NAMs) of the CRFBP(10kD)-CRF2 complex. Hits were confirmed by evaluating activity toward parental HEK293 cells, toward CRF2 in the absence of CRFBP(10kD), and toward CRF1 in vitro. Hits were further characterized in ex vivo electrophysiology assays that target: 1) the CRF1+ neurons in the central nucleus of the amygdala (CeA) of CRF1:GFP mice that express GFP under the CRF1 promoter, and 2) the CRF-induced potentiation of N-methyl-D-aspartic acid receptor (NMDAR)-mediated synaptic transmission in dopamine neurons in the ventral tegmental area (VTA). RESULTS: We found that CRFBP(10kD) potentiates CRF-intracellular Ca2+ release specifically via CRF2, indicating that CRFBP may possess excitatory roles in addition to the inhibitory role established by the N-terminal fragment of CRFBP, CRFBP(27kD). We identified novel small molecule CRFBP-CRF2 NAMs that do not alter the CRF1-mediated effects of exogenous CRF but blunt CRF-induced potentiation of NMDAR-mediated synaptic transmission in dopamine neurons in the VTA, an effect mediated by CRF2 and CRFBP. CONCLUSION: These results provide the first evidence of specific roles for CRF2 and CRFBP(10kD) in the modulation of neuronal activity and suggest that CRFBP(10kD)-CRF2 NAMs can be further developed for the treatment of stress-related disorders including alcohol and substance use disorders.

Pharmacological consequence of the A118G µ opioid receptor polymorphism on morphine- and fentanyl-mediated modulation of Ca²âº channels in humanized mouse sensory neurons.

BACKGROUND: The most common functional single nucleotide polymorphism of the human OPRM1 gene, A118G, has been shown to be associated with interindividual differences in opioid analgesic requirements, particularly with morphine, in patients with acute postoperative pain. The purpose of this study was to examine whether this polymorphism would modulate the morphine and fentanyl pharmacological profile of sensory neurons isolated from a humanized mouse model homozygous for either the 118A or 118G allele. METHODS: The coupling of wild-type and mutant µ opioid receptors to voltage-gated Ca channels after exposure to either ligand was examined by employing the whole cell variant of the patch-clamp technique in acutely dissociated trigeminal ganglion neurons. Morphine-mediated antinociception was measured in mice carrying either the 118AA or 118GG allele. RESULTS: The biophysical parameters (cell size, current density, and peak current amplitude potential) measured from both groups of sensory neurons were not significantly different. In 118GG neurons, morphine was approximately fivefold less potent and 26% less efficacious than that observed in 118AA neurons. On the other hand, the potency and efficacy of fentanyl were similar for both groups of neurons. Morphine-mediated analgesia in 118GG mice was significantly reduced compared with the 118AA mice. CONCLUSIONS: This study provides evidence to suggest that the diminished clinical effect observed with morphine in 118G carriers results from an alteration of the receptor's pharmacology in sensory neurons. In addition, the impaired analgesic response with morphine may explain why carriers of this receptor variant have an increased susceptibility to become addicted to opioids.

Varenicline, a partial agonist at neuronal nicotinic acetylcholine receptors, reduces nicotine-induced increases in 20% ethanol operant self-administration in Sprague-Dawley rats.

Alcohol and nicotine use disorders are often treated as separate diseases, despite evidence that approximately 80-90% of alcohol dependent individuals are also heavy smokers. Both nicotine and ethanol have been shown to interact with neuronal nicotinic acetylcholine receptors (nAChRs), suggesting these receptors are a common biological target for the effects of nicotine and ethanol in the brain. There are few studies that have examined the effects of co-administered nicotine and ethanol on the activity of nAChRs in rodents. In the present study, we show that Sprague-Dawley rats, a strain often used for nicotine studies but not as often for voluntary ethanol intake studies, will consume 20% ethanol using both the intermittent-access two-bottle-choice and operant self-administration models without the need for sucrose fading. We show that nicotine (0.2 mg/kg and 0.8 mg/kg, s.c.) significantly increases operant 20% ethanol self-administration and varenicline (2 mg/kg, s.c), a partial agonist at nAChRs, significantly decreases operant ethanol self-administration and nicotine-induced increases in ethanol self-administration. This suggests that nAChRs play an important role in increasing ethanol self-administration and that varenicline may be an efficacious treatment for alcohol and nicotine co-dependencies.