Tigecycline Reduces Ethanol Intake in Dependent and Nondependent Male and Female C57BL/6J Mice.

BACKGROUND: The chronic intermittent ethanol (CIE) paradigm is valuable for screening compounds for efficacy to reduce drinking traits related to alcohol use disorder (AUD), as it measures alcohol consumption and preference under physical dependence conditions. Air control-treated animals allow simultaneous testing of similarly treated, nondependent animals. As a consequence, we used CIE to test the hypothesis that tigecycline, a semisynthetic tetracycline similar to minocycline and doxycycline, would reduce alcohol consumption regardless of dependence status. METHODS: Adult C57BL/6J female and male mice were tested for tigecycline efficacy to reduce ethanol (EtOH) consumption using a standard CIE paradigm. The ability of tigecycline to decrease 2-bottle choice of 15% EtOH (15E) versus water intake in dependent (CIE vapor) and nondependent (air-treated) male and female mice was tested after 4 cycles of CIE vapor or air exposure using a within-subjects design and a dose-response. Drug doses of 0, 40, 60, 80, and 100 mg/kg in saline were administered intraperitoneally (0.01 ml/g body weight) and in random order, with a 1-hour pretreatment time. Baseline 15E intake was re-established prior to administration of subsequent injections, with a maximum of 2 drug injections tested per week. RESULTS: Tigecycline was found to effectively reduce high alcohol consumption in both dependent and nondependent female and male mice. CONCLUSIONS: Our data suggest that tigecycline may be a promising drug with novel pharmacotherapeutic characteristics for the treatment of mild-to-severe AUD in both sexes.

Effective Reduction of Acute Ethanol Withdrawal by the Tetracycline Derivative, Tigecycline, in Female and Male DBA/2J Mice.

BACKGROUND: Alcohol use disorder (AUD) is a spectrum disorder characterized by mild to severe symptoms, including potential withdrawal signs upon cessation of consumption. Approximately five hundred thousand patients with AUD undergo clinically relevant episodes of withdrawal annually (New Engl J Med, 2003, 348, 1786). Recent evidence indicates potential for drugs that alter neuroimmune pathways as new AUD therapies. We have previously shown the immunomodulatory drugs, minocycline and tigecycline, were effective in reducing ethanol (EtOH) consumption in both the 2-bottle choice and drinking-in-the-dark paradigms. Here, we test the hypothesis that tigecycline, a tetracycline derivative, will reduce the severity of EtOH withdrawal symptoms in a common acute model of alcohol withdrawal (AWD) using a single anesthetic dose of EtOH in seizure sensitive DBA/2J (DBA) mice. METHODS: Naïve adult female and male DBA mice were given separate injections of 4 g/kg i.p. EtOH with vehicle or tigecycline (0, 20, 40, or 80 mg/kg i.p.). The 80 mg/kg dose was tested at 3 time points (0, 4, and 7 hours) post EtOH treatment. Handling-induced convulsions (HICs) were measured before and then over 12 hours following EtOH injection. HIC scores and areas under the curve were tabulated. In separate mice, blood EtOH concentrations (BECs) were measured at 2, 4, and 7 hours postinjection of 4 g/kg i.p. EtOH in mice treated with 0 and 80 mg/kg i.p. tigecycline. RESULTS: AWD symptom onset, peak magnitude, and overall HIC severity were reduced by tigecycline drug treatment compared to controls. Tigecycline treatment was effective regardless of timing throughout AWD, with earlier treatment showing greater efficacy. Tigecycline showed a dose-responsive reduction in acute AWD convulsions, with no sex differences in efficacy. Importantly, tigecycline did not affect BECs over a time course of elimination. CONCLUSIONS: Tigecycline effectively reduced AWD symptoms in DBA mice at all times and dosages tested, making it a promising lead compound for development of a novel pharmacotherapy for AWD. Further studies are needed to determine the mechanism of tigecycline action.

Binge Ethanol Consumption Increases Inflammatory Pain Responses and Mechanical and Cold Sensitivity: Tigecycline Treatment Efficacy Shows Sex Differences.

BACKGROUND: Physicians have long reported that patients with chronic pain show higher tendencies for alcohol use disorder (AUD), and AUD patients appear to have higher pain sensitivities. The goal of this study was to test 2 hypotheses: (i) binge alcohol consumption increases inflammatory pain and mechanical and cold sensitivities; and (ii) tigecycline is an effective treatment for alcohol-mediated-increased pain behaviors and sensitivities. Both female and male mice were used to test the additional hypothesis that important sex differences in the ethanol (EtOH)-related traits would be seen. METHODS: "Drinking in the Dark" (DID) alcohol consuming and nondrinking control, female and male, adult C57BL/6J mice were evaluated for inflammatory pain behaviors and for the presence of mechanical and cold sensitivities. Inflammatory pain was produced by intraplantar injection of formalin (10 µl, 2.5% in saline). For cold sensation, a 20 µl acetone drop was used. Mechanical withdrawal threshold was measured by an electronic von Frey anesthesiometer. Efficacy of tigecycline (80 mg/kg i.p.) to reduce DID-related pain responses and sensitivity was tested. RESULTS: DID EtOH consumption increased inflammatory pain behavior, while it also produced sustained mechanical and cold sensitivities in both females and males. Tigecycline produced antinociceptive effects in males; a pro-nociceptive effect was seen in females in the formalin test. Likewise, the drug reduced both mechanical and cold sensitivities in males, but females showed an increase in sensitivity in both tests. CONCLUSIONS: Our results demonstrated that binge drinking increases pain, touch, and thermal sensations in both sexes. In addition, we have identified sex-specific effects of tigecycline on inflammatory pain, as well as mechanical and cold sensitivities. The development of tigecycline as an AUD pharmacotherapy may need consideration of its pro-nociceptive action in females. Further studies are needed to investigate the mechanism underlying the sex-specific differences in nociception.

Effective Reduction in High Ethanol Drinking by Semisynthetic Tetracycline Derivatives.

BACKGROUND: New pharmacotherapies to treat alcohol use disorders (AUD) are needed. Given the complex nature of AUD, there likely exist multiple novel drug targets. We, and others, have shown that the tetracycline drugs, minocycline and doxycycline, reduced ethanol (EtOH) drinking in mice. To test the hypothesis that suppression of high EtOH consumption is a general property of tetracyclines, we screened several derivatives for antidrinking activity using the Drinking-In-the-Dark (DID) paradigm. Active drugs were studied further using the dose-response relationship. METHODS: Adult female and male C57BL/6J mice were singly housed and the DID paradigm was performed using 20% EtOH over a 4-day period. Mice were administered a tetracycline or its vehicle 20 hours prior to drinking. Water and EtOH consumption was measured daily. Body weight was measured at the start of drug injections and after the final day of the experiment. Blood was collected for EtOH content measurement immediately following the final bout of drinking. RESULTS: Seven tetracyclines were tested at a 50 mg/kg dose. Only minocycline and tigecycline significantly reduced EtOH drinking, and doxycycline showed a strong effect size trend toward reduced drinking. Subsequent studies with these 3 drugs revealed a dose-dependent decrease in EtOH consumption for both female and male mice, with sex differences in efficacy. Minocycline and doxycycline reduced water intake at higher doses, although to a lesser degree than their effects on EtOH drinking. Tigecycline did not negatively affect water intake. The rank order of potency for reduction in EtOH consumption was minocycline > doxycycline > tigecycline, indicating efficacy was not strictly related to their partition coefficients or distribution constants. CONCLUSIONS: Due to its effectiveness in reducing high EtOH consumption coupled without an effect on water intake, tigecycline was found to be the most promising lead tetracycline compound for further study toward the development of a new pharmacotherapy for the treatment of AUD.

Bioinformatics analyses reveal age-specific neuroimmune modulation as a target for treatment of high ethanol drinking.

BACKGROUND: Use of in silico bioinformatics analyses has led to important leads in the complex nature of alcoholism at the genomic, epigenomic, and proteomic level, but has not previously been successfully translated to the development of effective pharmacotherapies. In this study, a bioinformatics approach led to the discovery of neuroimmune pathways as an age-specific druggable target. Minocycline, a neuroimmune modulator, reduced high ethanol (EtOH) drinking in adult, but not adolescent, mice as predicted a priori. METHODS: Age and sex-divergent effects in alcohol consumption were quantified in FVB/NJ × C57BL/6J F1 mice given access to 20% alcohol using a 4 h/d, 4-day drinking-in-dark (DID) paradigm. In silico bioinformatics pathway overrepresentation analysis for age-specific effects of alcohol in brain was performed using gene expression data collected in control and DID-treated, adolescent and adult, male mice. Minocycline (50 mg/kg i.p., once daily) or saline alone was tested for an effect on EtOH intake in the F1 and C57BL/6J (B6) mice across both age and gender groups. Effects of minocycline on the pharmacokinetic properties of alcohol were evaluated by comparing the rates of EtOH elimination between the saline- and minocycline-treated F1 and B6 mice. RESULTS: Age and gender differences in DID consumption were identified. Only males showed a clear developmental increase difference in drinking over time. In silico analyses revealed neuroimmune-related pathways as significantly overrepresented in adult, but not in adolescent, male mice. As predicted, minocycline treatment reduced drinking in adult, but not adolescent, mice. The age effect was present for both genders, and in both the F1 and B6 mice. Minocycline had no effect on the pharmacokinetic elimination of EtOH. CONCLUSIONS: Our results are a proof of concept that bioinformatics analysis of brain gene expression can lead to the generation of new hypotheses and a positive translational outcome for individualized pharmacotherapeutic treatment of high alcohol consumption.

The horizontal ladder test (HLT) protocol: a novel, optimized, and reliable means of assessing motor coordination in Sus scrofa domesticus.

Pigs can be an important model for preclinical biological research, including neurological diseases such as Alcohol Use Disorder. Such research often involves longitudinal assessment of changes in motor coordination as the disease or disorder progresses. Current motor coordination tests in pigs are derived from behavioral assessments in rodents and lack critical aspects of face and construct validity. While such tests may permit for the comparison of experimental results to rodents, a lack of validation studies of such tests in the pig itself may preclude the drawing of meaningful conclusions. To address this knowledge gap, an apparatus modeled after a horizontally placed ladder and where the height of the rungs could be adjusted was developed. The protocol that was employed within the apparatus mimicked the walk and turn test of the human standardized field sobriety test. Here, five Sinclair miniature pigs were trained to cross the horizontally placed ladder, starting at a rung height of six inches and decreasing to three inches in one-inch increments. It was demonstrated that pigs can reliably learn to cross the ladder, with few errors, under baseline/unimpaired conditions. These animals were then involved in a voluntary consumption of ethanol study where animals were longitudinally evaluated for motor coordination changes at baseline, 2.5, 5, 7.5, and 10% ethanol concentrations subsequently to consuming ethanol. Consistent with our predictions, relative to baseline performance, motor incoordination increased as voluntary consumption of escalating concentrations of ethanol increased. Together these data highlight that the horizontal ladder test (HLT) test protocol is a novel, optimized and reliable test for evaluating motor coordination as well as changes in motor coordination in pigs.

Alcohol-induced one-carbon metabolism impairment promotes dysfunction of DNA base excision repair in adult brain.

The brain is one of the major targets of chronic alcohol abuse. Yet the fundamental mechanisms underlying alcohol-mediated brain damage remain unclear. The products of alcohol metabolism cause DNA damage, which in conditions of DNA repair dysfunction leads to genomic instability and neural death. We propose that one-carbon metabolism (OCM) impairment associated with long term chronic ethanol intake is a key factor in ethanol-induced neurotoxicity, because OCM provides cells with DNA precursors for DNA repair and methyl groups for DNA methylation, both critical for genomic stability. Using histological (immunohistochemistry and stereological counting) and biochemical assays, we show that 3-week chronic exposure of adult mice to 5% ethanol (Lieber-Decarli diet) results in increased DNA damage, reduced DNA repair, and neuronal death in the brain. These were concomitant with compromised OCM, as evidenced by elevated homocysteine, a marker of OCM dysfunction. We conclude that OCM dysfunction plays a causal role in alcohol-induced genomic instability in the brain because OCM status determines the alcohol effect on DNA damage/repair and genomic stability. Short ethanol exposure, which did not disturb OCM, also did not affect the response to DNA damage, whereas additional OCM disturbance induced by deficiency in a key OCM enzyme, methylenetetrahydrofolate reductase (MTHFR) in Mthfr(+/-) mice, exaggerated the ethanol effect on DNA repair. Thus, the impact of long term ethanol exposure on DNA repair and genomic stability in the brain results from OCM dysfunction, and MTHFR mutations such as Mthfr 677C→T, common in human population, may exaggerate the adverse effects of ethanol on the brain.

Ethanol inhibition of undifferentiated rat neural progenitor cell replication can be prevented by chlorogenic acid via the NFATc4/CSE signaling pathway.

BACKGROUND: Prenatal ethanol exposure hinders oxidative stress-mediated neuroblast/neural progenitor cell proliferation by inhibiting G1-S transition, a process vital to neocortical development. We previously showed that ethanol elicits this redox imbalance by repressing cystathionine γ-lyase (CSE), the rate-limiting enzyme in the transsulfuration pathway in fetal brain and cultured cerebral cortical neurons. However, the mechanism by which ethanol impacts the CSE pathway in proliferating neuroblasts is not known. We conducted experiments to define the effects of ethanol on CSE regulation and the molecular signaling events that control this vital pathway. This enabled us to develop an intervention to prevent the ethanol-associated cytostasis. METHODS: Spontaneously immortalized undifferentiated E18 rat neuroblasts from brain cerebral cortex were exposed to ethanol to mimic an acute consumption pattern in humans. We performed loss- and gain-of-function studies to evaluate whether NFATc4 is a transcriptional regulator of CSE. The neuroprotective effects of chlorogenic acid (CGA) against the effects of ethanol were assessed using ROS and GSH/GSSG assays as measures of oxidative stress, transcriptional activation of NFATc4, and expression of NFATc4 and CSE by qRT-PCR and immunoblotting. RESULTS: Ethanol treatment of E18-neuroblast cells elicited oxidative stress and significantly reduced CSE expression with a concomitant decrease in NFATc4 transcriptional activation and expression. In parallel, inhibition of the calcineurin/NFAT pathway by FK506 exaggerated ethanol-induced CSE loss. In contrast, NFATc4 overexpression prevented loss of ethanol-induced CSE. CGA increased and activated NFATc4, amplified CSE expression, rescued ethanol-induced oxidative stress, and averted the cytostasis of neuroblasts by rescuing cyclin D1 expression. CONCLUSIONS: These findings demonstrate that ethanol can perturb CSE-dependent redox homeostasis by impairing the NFATc4 signaling pathway in neuroblasts. Notably, ethanol-associated impairments were rescued by genetic or pharmacological activation of NFATc4. Furthermore, we found a potential role for CGA in mitigating the ethanol-related neuroblast toxicity with a compelling connection to the NFATc4/CSE pathway.

Minocycline and Diacetyl Minocycline Eye Drops Reduce Ocular Neovascularization in Mice.

Purpose: To evaluate the efficacy of minocycline and a novel, modified minocycline analogue that lacks antimicrobial action, diacetyl minocycline (DAM), on choroidal neovascularization (CNV) in mice of both sexes. Methods: CNV was induced via laser injury in female and male C57BL/6J mice. Minocycline, DAM, or saline was administered via topical eye drops twice a day for 2 weeks starting the day after laser injury. CNV volume was measured using immunohistochemistry labeling and confocal microscopy. Results: Minocycline reduced lesion volume by 79% (P ≤ 0.0004) in female and male mice. DAM reduced lesion volume by 73% (P ≤ 0.001) in female and male mice. There was no significant difference in lesion volume between minocycline and DAM treatment groups or between female and male mice. Conclusions: Both minocycline and DAM eye drops significantly reduced laser-induced CNV lesion volume in female and male mice. While oral tetracyclines have been shown to mitigate pathologic neovascularization in both preclinical studies and clinical trials, the present data are the first to suggest that tetracycline derivatives may be effective to reduce pathologic CNV when administered via topical eye drops. However, the action is unrelated to antimicrobial action. Targeted delivery of these medications via eye drops may reduce the potential for systemic side effects. Translational Relevance: Topical administration of minocycline and/or DAM via eye drops may represent a novel therapeutic strategy for disorders involving pathologic CNV.

The Horizontal Ladder Test (HLT) protocol: A novel, optimized, and reliable means of assessing motor coordination in Sus scrofa domesticus.

Pigs can be an important model for preclinical biological research, including neurological diseases such as Alcohol Use Disorder. Such research often involves longitudinal assessment of changes in motor coordination as the disease or disorder progresses. Current motor coordination tests in pigs are derived from behavioral assessments in rodents and lack critical aspects of face and construct validity. While such tests may permit for the comparison of experimental results to rodents, a lack of validation studies of such tests in the pig itself may preclude the drawing of meaningful conclusions. Here, we present a novel, optimized, and reliable horizontal ladder test (HLT) test protocol for evaluating motor coordination in pigs and an initial validation of its construct validity using voluntary alcohol consumption as an experimental manipulation.

Sex Differences in the Brain Transcriptome Related to Alcohol Effects and Alcohol Use Disorder.

There is compelling evidence that sex and gender have crucial roles in excessive alcohol (ethanol) consumption. Here, we review some of the data from the perspective of brain transcriptional differences between males and females, focusing on rodent animal models. A key emerging transcriptional feature is the role of neuroimmune processes. Microglia are the resident neuroimmune cells in the brain and exhibit substantial functional differences between males and females. Selective breeding for binge ethanol consumption and the impacts of chronic ethanol consumption and withdrawal from chronic ethanol exposure all demonstrate sex-dependent neuroimmune signatures. A focus is on resolving sex-dependent differences in transcriptional responses to ethanol at the neurocircuitry level. Sex-dependent transcriptional differences are found in the extended amygdala and the nucleus accumbens. Telescoping of ethanol consumption is found in some, but not all, studies to be more prevalent in females. Recent transcriptional studies suggest that some sex differences may be due to female-dependent remodeling of the primary cilium. An interesting theme appears to be developing: at least from the animal model perspective, even when males and females are phenotypically similar, they differ significantly at the level of the transcriptome.

Ethanol Impairs NRF2/Antioxidant and Growth Signaling in the Intact Placenta In Vivo and in Human Trophoblasts.

NRF2 is a redox-sensitive transcription factor that depending on the duration or magnitude of the stress, either translocates to the nucleus (beneficial) or is degraded in the cytosol (harmful). However, the role of NRF2-based mechanism(s) under ethanol (E)-induced developmental toxicity in the placental context remains unknown. Here, we used a rat prenatal model of maternal alcohol stress consisting of intermittent ethanol vapor (IEV) daily from GD11 to GD20 with a 6 h ON/18 h OFF in a vapor chamber and in vitro placental model consisting of HTR-8 trophoblasts exposed to 86 mM of E for either 24 h or 48 h. The role of NRF2 was evaluated through the NRF2-transactivation reporter assay, qRT-PCR, and Western blotting for NRF2 and cell growth-promoting protein, and cell proliferation assay. In utero and in vitro E decreased the nuclear NRF2 content and diminished its transactivation ability along with dysregulation of the proliferation indices, PCNA, CYCLIN-D1, and p21. This was associated with a ~50% reduction in cell proliferation in vitro in trophoblasts. Interestingly, this was found to be partially rescued by ectopic Nrf2 overexpression. These results indicate that ethanol-induced dysregulation of NRF2 coordinately regulates PCNA/CYCLIN-D1/p21 involving growth network, at least partially to set a stage for placental perturbations.

Can serotonin transporter genotype predict serotonergic function, chronicity, and severity of drinking?

Serotonin transporter (5-HTT) activity is greater in carriers of the long (L) vs. short (S) alleles of the 5-HTT-linked polymorphic region (5'-HTTLPR) among healthy control subjects but not alcohol-dependent adults. In 198 alcoholics, we determined the relationship between current or lifetime drinking and platelet 5-HTT function and density among allelic variants of the 5'-HTTLPR. SS subjects were younger than L-carriers (LL and LS) (p<0.0085) and had fewer years of lifetime drinking. For L-carriers, the mean of Bmax for paroxetine binding, but not Vmax for serotonin (5-HT) uptake, was lower than that for SS subjects (p<0.05). More L-carriers than their SS counterparts had Vmax for 5-HT uptake below 200 nmol/10(7) platelets-min (p<0.05) and Bmax for paroxetine binding below 600 nmol/mg protein (p<0.06). Current drinking (drinks per day during the past 14 days) correlated positively with Km and Vmax of platelet 5-HT uptake (p<0.05) and negatively with Bmax, but not Kd, of paroxetine binding (p<0.05) for L-carriers alone. Years of lifetime drinking correlated negatively with Km and Vmax of platelet 5-HT uptake (p<0.05) and B(max), but not Kd, of paroxetine binding (p<0.05) for L-carriers alone. Among L-carriers alone, there were higher levels of platelet 5-HT uptake and lower levels of platelet paroxetine binding with increased drinking, and more lifetime drinking was associated with modestly lower levels of 5-HT uptake and paroxetine binding. Thus, 5-HTT expression varies with current and lifetime drinking in L-carriers alone.

Transcriptional signatures of cellular plasticity in mice lacking the alpha1 subunit of GABAA receptors.

GABAA receptors mediate the majority of inhibitory neurotransmission in the CNS. Genetic deletion of the alpha1 subunit of GABAA receptors results in a loss of alpha1-mediated fast inhibitory currents and a marked reduction in density of GABAA receptors. A grossly normal phenotype of alpha1-deficient mice suggests the presence of neuronal adaptation to these drastic changes at the GABA synapse. We used cDNA microarrays to identify transcriptional fingerprints of cellular plasticity in response to altered GABAergic inhibition in the cerebral cortex and cerebellum of alpha1 mutants. In silico analysis of 982 mutation-regulated transcripts highlighted genes and functional groups involved in regulation of neuronal excitability and synaptic transmission, suggesting an adaptive response of the brain to an altered inhibitory tone. Public gene expression databases permitted identification of subsets of transcripts enriched in excitatory and inhibitory neurons as well as some glial cells, providing evidence for cellular plasticity in individual cell types. Additional analysis linked some transcriptional changes to cellular phenotypes observed in the knock-out mice and suggested several genes, such as the early growth response 1 (Egr1), small GTP binding protein Rac1 (Rac1), neurogranin (Nrgn), sodium channel beta4 subunit (Scn4b), and potassium voltage-gated Kv4.2 channel (Kcnd2) as cell type-specific markers of neuronal plasticity. Furthermore, transcriptional activation of genes enriched in Bergman glia suggests an active role of these astrocytes in synaptic plasticity. Overall, our results suggest that the loss of alpha1-mediated fast inhibition produces diverse transcriptional responses that act to regulate neuronal excitability of individual neurons and stabilize neuronal networks, which may account for the lack of severe abnormalities in alpha1 null mutants.

Mu (mu) opioid receptor regulation of ethanol-induced dopamine response in the ventral striatum: evidence of genotype specific sexual dimorphic epistasis.

BACKGROUND: Ethanol stimulates the dopaminergic mesoaccumbal pathway, which is thought to play a role in ethanol reinforcement. Mu (mu)-opioid (MOP) receptors modulate accumbal dopamine activity, but it is not clear whether MOP receptors are involved in the mechanism of ethanol-stimulated accumbal dopamine release. METHODS: We investigated the role that MOP receptors play in ethanol (2.0 g/kg)-stimulated accumbal dopamine release by using MOP receptor knockout mice (C57BL/6J-129SvEv and congenic C57BL/6J genotypes) along with blockade of MOP receptors with a mu1 selective antagonist (naloxonazine). RESULTS: Both gene deletion and pharmacological antagonism of the MOP receptor decreased ethanol-stimulated accumbal dopamine release compared with controls with female mice showing a larger effect in the C57BL/6J-129SvEv genotype. However, both male and female mice showed reduced ethanol-stimulated dopamine release in the congenic MOP receptor knockout mice (C57BL/6J). No differences in the time course of dialysate ethanol concentration were found in any of the experiments. CONCLUSIONS: The data demonstrate the existence of a novel interaction between genotype and sex in the regulation of ethanol-stimulated mesolimbic dopamine release by the MOP receptor. This implies that a more complete understanding of the epistatic influences on the MOP receptor and mesolimbic dopamine function may provide more effective pharmacotherapeutic interventions in the treatment of alcoholism.

Computer automated movement detection for the analysis of behavior.

Currently, measuring ethanol behaviors in flies depends on expensive image analysis software or time intensive experimental observation. We have designed an automated system for the collection and analysis of locomotor behavior data, using the IEEE 1394 acquisition program dvgrab, the image toolkit ImageMagick and the programming language Perl. In the proposed method, flies are placed in a clear container and a computer-controlled camera takes pictures at regular intervals. Digital subtraction removes the background and non-moving flies, leaving white pixels where movement has occurred. These pixels are tallied, giving a value that corresponds to the number of animals that have moved between images. Perl scripts automate these processes, allowing compatibility with high-throughput genetic screens. Four experiments demonstrate the utility of this method, the first showing heat-induced locomotor changes, the second showing tolerance to ethanol in a climbing assay, the third showing tolerance to ethanol by scoring the recovery of individual flies, and the fourth showing a mouse's preference for a novel object. Our lab will use this method to conduct a genetic screen for ethanol-induced hyperactivity and sedation, however, it could also be used to analyze locomotor behavior of any organism.

Preliminary data on the association among the serotonin transporter polymorphism, subjective alcohol experiences, and drinking behavior.

OBJECTIVE: Individual differences in subjective responses to alcohol are believed to have a genetic basis and have been associated with increased risk of alcohol-related problems. There are, however, conflicting results from past studies, perhaps owing to differences in subjective alcohol effects by limb of the blood alcohol curve and the passage of time. The current pilot study evaluated relations among serotonin transporter (SERT) genotype, subjective alcohol responses, and drinking behavior across both the ascending and descending limbs of the blood alcohol curve. METHOD: Participants (N=222; 68% male) were administered alcohol (target blood alcohol concentration of .06%) with a subsample (n=86) providing genetic data. Following a social stressor, participants were provided the opportunity to engage in ad libitum alcohol consumption. RESULTS: SERT transporter was not significantly associated with ad lib drinking or subjective alcohol effects at individual time points, although a trend toward a SERT by blood alcohol concentration limb interaction was observed for ad lib drinking. In addition, SERT genotype predicted acute tolerance to alcohol effects, with participants homozygous for the long SERT allele developing acute tolerance more rapidly than other genotypes. CONCLUSIONS: Although SERT genotype was not reliably associated with ad lib drinking behavior, the results suggest that individuals with the long-long (LL) genotype may develop acute tolerance to alcohol effects more rapidly than heterozygotes or individuals homozygous for the short SERT allele.

The Cstf2t Polyadenylation Gene Plays a Sex-Specific Role in Learning Behaviors in Mice.

Polyadenylation is an essential mechanism for the processing of mRNA 3' ends. CstF-64 (the 64,000 Mr subunit of the cleavage stimulation factor; gene symbol Cstf2) is an RNA-binding protein that regulates mRNA polyadenylation site usage. We discovered a paralogous form of CstF-64 called τCstF-64 (Cstf2t). The Cstf2t gene is conserved in all eutherian mammals including mice and humans, but the τCstF-64 protein is expressed only in a subset of mammalian tissues, mostly testis and brain. Male mice that lack Cstf2t (Cstf2t-/- mice) experience disruption of spermatogenesis and are infertile, although female fertility is unaffected. However, a role for τCstF-64 in the brain has not yet been determined. Given the importance of RNA polyadenylation and splicing in neuronal gene expression, we chose to test the hypothesis that τCstF-64 is important for brain function. Male and female 185-day old wild type and Cstf2t-/- mice were examined for motor function, general activity, learning, and memory using rotarod, open field activity, 8-arm radial arm maze, and Morris water maze tasks. Male wild type and Cstf2t-/- mice did not show differences in learning and memory. However, female Cstf2t-/- mice showed significantly better retention of learned maze tasks than did female wild type mice. These results suggest that τCstf-64 is important in memory function in female mice. Interestingly, male Cstf2t-/- mice displayed less thigmotactic behavior than did wild type mice, suggesting that Cstf2t may play a role in anxiety in males. Taken together, our studies highlight the importance of mRNA processing in cognition and behavior as well as their established functions in reproduction.

Glycine receptor knock-in mice and hyperekplexia-like phenotypes: comparisons with the null mutant.

Strychnine-sensitive glycine receptors (GlyRs) inhibit neurotransmission in the spinal cord and brainstem. To better define the function of this receptor in vivo, we constructed a point mutation that impairs receptor function in the alpha1-subunit and compared these knock-in mice to oscillator (spdot) mice lacking functional GlyR alpha1-subunits. Mutation of the serine residue at amino acid 267 to glutamine (alpha1S267Q) results in a GlyR with normal glycine potency but decreased maximal currents, as shown by electrophysiological recordings using Xenopus oocytes. In addition, single-channel recordings using human embryonic kidney 293 cells indicated profoundly altered properties of the mutated GlyR. We produced knock-in mice bearing the GlyR alpha1 S267Q mutation to assess the in vivo consequences of selectively decreasing GlyR efficacy. Chloride uptake into brain synaptoneurosomes from knock-in mice revealed decreased responses to maximally effective glycine concentrations, although wild-type levels of GlyR expression were observed using 3H-strychnine binding and immunoblotting. A profound increase in the acoustic startle response was observed in knock-in mice as well as a "limb clenching" phenotype. In contrast, no changes in coordination or pain perception were observed using the rotarod or hot-plate tests, and there was no change in GABA(A)-receptor-mediated chloride uptake. Homozygous S267Q knock-in mice, like homozygous spdot mice, exhibited seizures and died within 3 weeks of birth. In heterozygous spdot mice, both decreased 3H-strychnine binding and chloride flux were observed; however, neither enhanced acoustic startle responses nor limb clenching were seen. These data demonstrate that a dominant-negative point mutation in GlyR disrupting normal function can produce a more dramatic phenotype than the corresponding recessive null mutation, and provides a new animal model to evaluate GlyR function in vivo.

Perturbation of chemokine networks by gene deletion alters the reinforcing actions of ethanol.

Microarray analysis of human alcoholic brain and cultured cells exposed to ethanol showed significant changes in expression of genes related to immune or inflammatory responses, including chemokines and chemokine receptors. To test the hypothesis that chemokines exhibit previously undiscovered pleiotropic effects important for the behavioral actions of ethanol, we studied mutant mice with deletion of the Ccr2, Ccr5, Ccl2 or Ccl3 genes. Deletion of Ccr2, Ccl2 (females) or Ccl3 in mice resulted in lower preference for alcohol and consumption of lower amounts of alcohol in a two-bottle choice test as compared with wild-type mice. Ethanol treatment (2.5 g/kg, i.p.) induced stronger conditioned taste aversion in Ccr2, Ccl2 or Ccl3 null mutant mice than in controls. Ccr2 and Ccr5 null mutant mice did not differ from wild-type mice in ethanol-induced loss of righting reflex (LORR), but mice lacking Ccl2 or Ccl3 showed longer LORR than wild-type mice. There were no differences between mutant strains and wild-type mice in severity of ethanol-induced withdrawal. Genetic mapping of chromosome 11 for the Ccl2 and Ccl3 genes (46.5 and 47.6 cM, respectively) revealed that an alcohol-induced LORR QTL region was contained within the introgressed region derived from 129/SvJ, which may cause some behavioral phenotypes observed in the null mice. On the contrary, known QTLs on Chr 9 are outside of 129/SvJ region in Ccr2 and Ccr5 (71.9 and 72.0 cM, respectively) null mutant mice. These data show that disruption of the chemokine network interferes with motivational effects of alcohol.