Physiological Exploration of the Long Term Evolutionary Selection against Expression of N-Glycolylneuraminic Acid in the Brain.

All vertebrate cell surfaces display a dense glycan layer often terminated with sialic acids, which have multiple functions due to their location and diverse modifications. The major sialic acids in most mammalian tissues are N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), the latter being derived from Neu5Ac via addition of one oxygen atom at the sugar nucleotide level by CMP-Neu5Ac hydroxylase (Cmah). Contrasting with other organs that express various ratios of Neu5Ac and Neu5Gc depending on the variable expression of Cmah, Neu5Gc expression in the brain is extremely low in all vertebrates studied to date, suggesting that neural expression is detrimental to animals. However, physiological exploration of the reasons for this long term evolutionary selection has been lacking. To explore the consequences of forced expression of Neu5Gc in the brain, we have established brain-specific Cmah transgenic mice. Such Neu5Gc overexpression in the brain resulted in abnormal locomotor activity, impaired object recognition memory, and abnormal axon myelination. Brain-specific Cmah transgenic mice were also lethally sensitive to a Neu5Gc-preferring bacterial toxin, even though Neu5Gc was overexpressed only in the brain and other organs maintained endogenous Neu5Gc expression, as in wild-type mice. Therefore, the unusually strict evolutionary suppression of Neu5Gc expression in the vertebrate brain may be explained by evasion of negative effects on neural functions and by selection against pathogens.

Object exploration in the developing rat: methodological considerations.

The current study was conducted to characterize the ontogeny of novel object recognition in rats. Initial testing (Experiment 1) was conducted in a square arena and it was observed that 21-day-old animals would often pause in the corners, greatly increasing between-subject variability and performance in this test. Significantly greater object exploration and less variability were obtained using a circular arena. In Experiment 2, we report object exploration in 21, 35, 42, and 90-day-old male and female Sprague-Dawley rats using a circular arena. The results show that measures of locomotor activity, object exploration, and within session habituation of these behaviors were surprisingly similar across all ages. Gender differences in locomotor activity were not observed until 42 days of age. Reliable recognition memory was observed at all ages. It is concluded that the novel object recognition test appears well suited for use in young rats.

Tropisetron, a 5-HT(3) receptor antagonist, enhances object exploration in intact female rats.

The effects of a 5-HT(3) receptor antagonist, tropisetron, on cognitive functions were evaluated using the object-recognition test in estrous (postovulatory) and in diestrous female rats. Recognition was measured by the ability of rats to discriminate between a familiar and a new object in a T-maze after a 3-h delay. Rats from both stages spent equivalent amounts of time exploring the objects on trial 1. Three hours after trial 1, trial 2 (test trial) was initiated. Before the test trial, rats were injected with either saline or 1.5 or 2.5 mg/kg tropisetron. During the test trial, one arm of a T-maze contained an object from trial 1 (familiar) and a new object (novel) was introduced into the other arm. Rats from both stages responded to tropisetron by showing a greater percentage of time exploring the novel object. These findings indicate that tropisetron facilitates cognition in female rats by improving the recognition of familiar information.

Alcohol Use Disorder: The Role of Medication in Recovery.

The misuse of alcohol in the United States continues to take a large toll on society, resulting in the deaths of about 88,000 Americans per year. Moreover, it is estimated that nearly 14.6 million Americans currently meet diagnostic criteria for current alcohol use disorder (AUD). However, very few individuals receive treatment, with an even smaller portion receiving medications approved by the U.S. Food and Drug Administration (FDA) for the treatment of AUD, despite scientifically rigorous evidence showing the benefits of combining medication approved for treating AUD with evidence-based behavioral therapy. These benefits include higher rates of abstinence and less risk of relapse to heavy drinking, with associated improvements in medical and mental health and in quality of life. This review provides an overview of FDA-approved medications and "off-label" drugs for the treatment of AUD. The article emphasizes that AUD medical advice and prescription recommendations should come from professionals with training in the treatment of AUD and that treatment plans should consider medication in conjunction with evidence-based behavioral therapy. Finally, this review notes the limited number of medications available and the continued need for the development of new pharmacotherapies to optimize AUD recovery goals.

Correspondence Between Perceived Pubertal Development and Hormone Levels in 9-10 Year-Olds From the Adolescent Brain Cognitive Development Study.

Aim: To examine individual variability between perceived physical features and hormones of pubertal maturation in 9-10-year-old children as a function of sociodemographic characteristics. Methods: Cross-sectional metrics of puberty were utilized from the baseline assessment of the Adolescent Brain Cognitive Development (ABCD) Study-a multi-site sample of 9-10 year-olds (n = 11,875)-and included perceived physical features via the pubertal development scale (PDS) and child salivary hormone levels (dehydroepiandrosterone and testosterone in all, and estradiol in females). Multi-level models examined the relationships among sociodemographic measures, physical features, and hormone levels. A group factor analysis (GFA) was implemented to extract latent variables of pubertal maturation that integrated both measures of perceived physical features and hormone levels. Results: PDS summary scores indicated more males (70%) than females (31%) were prepubertal. Perceived physical features and hormone levels were significantly associated with child's weight status and income, such that more mature scores were observed among children that were overweight/obese or from households with low-income. Results from the GFA identified two latent factors that described individual differences in pubertal maturation among both females and males, with factor 1 driven by higher hormone levels, and factor 2 driven by perceived physical maturation. The correspondence between latent factor 1 scores (hormones) and latent factor 2 scores (perceived physical maturation) revealed synchronous and asynchronous relationships between hormones and concomitant physical features in this large young adolescent sample. Conclusions: Sociodemographic measures were associated with both objective hormone and self-report physical measures of pubertal maturation in a large, diverse sample of 9-10 year-olds. The latent variables of pubertal maturation described a complex interplay between perceived physical changes and hormone levels that hallmark sexual maturation, which future studies can examine in relation to trajectories of brain maturation, risk/resilience to substance use, and other mental health outcomes.

A description of the ABCD organizational structure and communication framework.

The Adolescent Brain Cognitive Development (ABCD) study is designed to be the largest study of brain development and child health in the United States, performing comprehensive assessments of 11,500 children repeatedly for 10 years. An endeavor of this magnitude requires an organized framework of governance and communication that promotes collaborative decision-making and dissemination of information. The ABCD consortium structure, built upon the Matrix Management approach of organizational theory, facilitates the integration of input from all institutions, numerous internal workgroups and committees, federal partners, and external advisory groups to make use of a broad range of expertise to ensure the study's success.

Transplantation of wild-type mouse hematopoietic stem and progenitor cells ameliorates deficits in a mouse model of Friedreich's ataxia.

Friedreich's ataxia (FRDA) is an incurable autosomal recessive neurodegenerative disease caused by reduced expression of the mitochondrial protein frataxin due to an intronic GAA-repeat expansion in the FXN gene. We report the therapeutic efficacy of transplanting wild-type mouse hematopoietic stem and progenitor cells (HSPCs) into the YG8R mouse model of FRDA. In the HSPC-transplanted YG8R mice, development of muscle weakness and locomotor deficits was abrogated as was degeneration of large sensory neurons in the dorsal root ganglia (DRGs) and mitochondrial capacity was improved in brain, skeletal muscle, and heart. Transplanted HSPCs engrafted and then differentiated into microglia in the brain and spinal cord and into macrophages in the DRGs, heart, and muscle of YG8R FRDA mice. We observed the transfer of wild-type frataxin and Cox8 mitochondrial proteins from HSPC-derived microglia/macrophages to FRDA mouse neurons and muscle myocytes in vivo. Our results show the HSPC-mediated phenotypic rescue of FRDA in YG8R mice and suggest that this approach should be investigated further as a strategy for treating FRDA.

Discovery of Potent and Selective Inhibitors of Phosphodiesterase 1 for the Treatment of Cognitive Impairment Associated with Neurodegenerative and Neuropsychiatric Diseases.

A diverse set of 3-aminopyrazolo[3,4-d]pyrimidinones was designed and synthesized. The structure-activity relationships of these polycyclic compounds as phosphodiesterase 1 (PDE1) inhibitors were studied along with their physicochemical and pharmacokinetic properties. Systematic optimizations of this novel scaffold culminated in the identification of a clinical candidate, (6aR,9aS)-2-(4-(6-fluoropyridin-2-yl)benzyl)-5-methyl-3-(phenylamino)-5,6a,7,8,9,9a-hexahydrocyclopenta[4,5]imidazo[1,2-a]pyrazolo[4,3-e]pyrimidin-4-(2H)-one phosphate (ITI-214), which exhibited picomolar inhibitory potency for PDE1, demonstrated excellent selectivity against all other PDE families and showed good efficacy in vivo. Currently, this investigational new drug is in Phase I clinical development and being considered for the treatment of several indications including cognitive deficits associated with schizophrenia and Alzheimer's disease, movement disorders, attention deficit and hyperactivity disorders, and other central nervous system (CNS) and non-CNS disorders.

Gain of Toxicity from ALS/FTD-Linked Repeat Expansions in C9ORF72 Is Alleviated by Antisense Oligonucleotides Targeting GGGGCC-Containing RNAs.

Hexanucleotide expansions in C9ORF72 are the most frequent genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Disease mechanisms were evaluated in mice expressing C9ORF72 RNAs with up to 450 GGGGCC repeats or with one or both C9orf72 alleles inactivated. Chronic 50% reduction of C9ORF72 did not provoke disease, while its absence produced splenomegaly, enlarged lymph nodes, and mild social interaction deficits, but not motor dysfunction. Hexanucleotide expansions caused age-, repeat-length-, and expression-level-dependent accumulation of RNA foci and dipeptide-repeat proteins synthesized by AUG-independent translation, accompanied by loss of hippocampal neurons, increased anxiety, and impaired cognitive function. Single-dose injection of antisense oligonucleotides (ASOs) that target repeat-containing RNAs but preserve levels of mRNAs encoding C9ORF72 produced sustained reductions in RNA foci and dipeptide-repeat proteins, and ameliorated behavioral deficits. These efforts identify gain of toxicity as a central disease mechanism caused by repeat-expanded C9ORF72 and establish the feasibility of ASO-mediated therapy.

Appoptosin-Mediated Caspase Cleavage of Tau Contributes to Progressive Supranuclear Palsy Pathogenesis.

Progressive supranuclear palsy (PSP) is a movement disorder characterized by tau neuropathology where the underlying mechanism is unknown. An SNP (rs1768208 C/T) has been identified as a strong risk factor for PSP. Here, we identified a much higher T-allele occurrence and increased levels of the pro-apoptotic protein appoptosin in PSP patients. Elevations in appoptosin correlate with activated caspase-3 and caspase-cleaved tau levels. Appoptosin overexpression increased caspase-mediated tau cleavage, tau aggregation, and synaptic dysfunction, whereas appoptosin deficiency reduced tau cleavage and aggregation. Appoptosin transduction impaired multiple motor functions and exacerbated neuropathology in tau-transgenic mice in a manner dependent on caspase-3 and tau. Increased appoptosin and caspase-3-cleaved tau were also observed in brain samples of patients with Alzheimer's disease and frontotemporal dementia with tau inclusions. Our findings reveal a novel role for appoptosin in neurological disorders with tau neuropathology, linking caspase-3-mediated tau cleavage to synaptic dysfunction and behavioral/motor defects.

Effects of naltrexone alone and in combination with acamprosate on the alcohol deprivation effect in rats.

Previous research in our laboratory has shown that responding for ethanol increases after a period of imposed deprivation during which no ethanol is available (the alcohol deprivation effect). This selective increase in responding for ethanol was blocked by chronic administration of acamprosate. In the present study the effects of naltrexone and the combination of naltrexone+acamprosate on oral ethanol self-administration were examined following an imposed period of abstinence. Male Wistar rats were trained to respond for ethanol (10% w/v) or water in a two-lever free-choice condition. After training, separate groups of rats received chronic injections (2 x /day) of saline, naltrexone, or naltrexone+acamprosate during a 5-day period of abstinence. Ethanol self-administration was tested in all groups of rats on the last day of abstinence, 30 min after the last drug injection. Responding for ethanol increased significantly following the deprivation period in animals treated with saline. Chronic administration of naltrexone and the combination naltrexone+acamprosate blocked the increased ethanol consumption following the imposed abstinence period on post-deprivation Day 1. On post-deprivation Day 2, the combination of acamprosate with naltrexone blocked the rebound increase in ethanol consumption observed in animals treated with a low dose of naltrexone. These results support the hypothesis that naltrexone and acamprosate are effective in modulating aspects of alcohol-seeking behavior, and under certain situations may be more effective in combination.

The effects of methylphenidate on novel object exploration in weanling and periadolescent rats.

Methylphenidate (Ritalin) is used in the treatment of attention-deficit hyperactivity disorder. Surprisingly, little research has been conducted on the effects of methylphenidate during early development. Therefore, the present study was conducted to examine the effects of methylphenidate on object exploration in developing rats. Male and female weanling (21-day-old) and periadolescent (34-day-old) Sprague-Dawley rats were tested after acute or chronic treatment with methylphenidate. In weanling rats, chronic methylphenidate (5.0 mg/kg) increased locomotor activity and disrupted novel object exploration. In periadolescent rats, methylphenidate disrupted exploration of the novel object, but had no effect on locomotor activity at any dose tested. Periadolescent rats appear to be less sensitive to methylphenidate-induced changes in activity compared to weanling animals, whereas methylphenidate disrupted novel object exploration in both ages. Our results suggest that methylphenidate may alter recognition memory and/or reactivity to or preference for novelty.

The effects of Coenzyme Q10 on locomotor and behavioral activity in young and aged C57BL/6 mice.

To explore the possibility that Coenzyme Q10 (CoQ10) supplementation stabilizes psychomotor behavioral function in the aging organism, the behavioral effects of CoQ10 were evaluated in young adult male C57BL/6 mice (3 months of age) and aged C57BL/6 mice (24 months of age). Mice treated with CoQ10 exhibited significantly greater locomotor activity as reflected by an increase in square crosses than non-drug controls. The administration of CoQ10 increased all aspects of exploratory behavior in the open field. The effect was uniform across all mice and did not interact with age. Younger animals and aged animals treated with CoQ10 may adapt rapidly to novel areas, or they are less fearful of exploration. The behavioral activation observed in CoQ10 treated mice may be the result of increased locomotor activity, psychomotor stimulation, or decreased anxiety.

Animal models of motivation for drinking in rodents with a focus on opioid receptor neuropharmacology.

Ethanol, like other drugs of abuse, has motivating properties that can be developed as animal models of self-administration. A major strength of the operant approach where an animal must work to obtain ethanol is that it reduces confounds due to palatability and controls for nonspecific malaise-inducing effects. In the domain of opioid peptide systems, limited access paradigms have good predictive validity. In addition, animal models of excessive drinking-either environmentally or genetically induced-also appear sensitive to blockade or inactivation of opioid peptide receptors. Ethanol availability can be predicted by cues associated with positive reinforcement, and these models are sensitive to the administration of opioid antagonists. Perhaps most exciting are the recent results suggesting that the key element in opioid peptide systems that is important for the positive reinforcing effects of ethanol is the mu-opioid receptor. How exactly ethanol modulates mu-receptor function will be a major challenge of future research. Nevertheless, the apparently critical role of the mu receptor in ethanol reinforcement refocuses the neuropharmacology of ethanol reinforcement in the opioid peptide domain and opens a novel avenue for exploring medications for treating alcoholism.

The effect of cocaine on rotarod performance in male C57BL/6J mice.

There is surprisingly little research examining the effect of cocaine on motor learning. Given that changes in motor activity can confound behavioral assays of learning and memory a direct assessment of cocaine on motor learning seems warranted. The present study was conducted to examine the effect of cocaine on motor learning using an accelerating rotarod test in adult male C57BL/6J mice. Mice were given an injection of either saline or cocaine (10mg/kg, i.p.) for 6 consecutive days prior to rotarod training (Pre-exposure). In the first phase of training (Phase I), mice were given an injection of either saline or cocaine 10min prior to the start of each day's training on the rotarod for 6 consecutive days. In the second phase (Phase II), half the animals continued to receive the same drug during training, while the other half were switched from saline to cocaine or from cocaine to saline. All mice exhibited motor learning as evidenced by an increased latency to fall across days. Animals that received cocaine injections exhibited significantly longer latencies to fall on days 3-6 compared to those mice receiving saline. This enhanced performance was lost when cocaine-injected animals were switched to saline on day 7. It is hypothesized that the performance enhancing effects of cocaine are due to the increased stamina and/or psychomotor stimulation and not the result of enhanced motor learning as the increment in performance was lost when the drug was discontinued.

Methylphenidate restores novel object recognition in DARPP-32 knockout mice.

Previously, we have shown that Dopamine- and cAMP-regulated phosphoprotein of 32kDa (DARPP-32) knockout mice required significantly more trials to reach criterion than wild-type mice in an operant reversal-learning task. The present study was conducted to examine adult male and female DARPP-32 knockout mice and wild-type controls in a novel object recognition test. Wild-type and knockout mice exhibited comparable behavior during the initial exploration trials. As expected, wild-type mice exhibited preferential exploration of the novel object during the substitution test, demonstrating recognition memory. In contrast, knockout mice did not show preferential exploration of the novel object, instead exhibiting an increase in exploration of all objects during the test trial. Given that the removal of DARPP-32 is an intracellular manipulation, it seemed possible to pharmacologically restore some cellular activity and behavior by stimulating dopamine receptors. Therefore, a second experiment was conducted examining the effect of methylphenidate. The results show that methylphenidate increased horizontal activity in both wild-type and knockout mice, though this increase was blunted in knockout mice. Pretreatment with methylphenidate significantly impaired novel object recognition in wild-type mice. In contrast, pretreatment with methylphenidate restored the behavior of DARPP-32 knockout mice to that observed in wild-type mice given saline. These results provide additional evidence for a functional role of DARPP-32 in the mediation of processes underlying learning and memory. These results also indicate that the behavioral deficits in DARPP-32 knockout mice may be restored by the administration of methylphenidate.

Novel object exploration in mice: not all objects are created equal.

Object exploration is an increasingly popular experimental paradigm in behavioral sciences. We have begun a series of studies with mice specifically looking at the parameters that influence behaviors in this test. The aim of the present study was to examine the effect of object type on performance in the object exploration test. More specifically, adult male C57BL/6J mice were trained and tested using objects that could be climbed (CLIMB) or with those that could only be touched (TOUCH). The results show that activity is affected by the presentation of objects, with object type interacting with some of these changes. C57 mice explored objects that can be climbed over significantly longer than objects that can only be touched and a more rapid habituation was observed using objects that could only be touched. Robust recognition memory was observed in both groups of mice, however mice in the CLIMB group exhibited a significantly greater discrimination index compared to mice in the TOUCH group. Taken together, these findings demonstrate that the selection of objects is of critical importance and it is recommended that special attention be given to the functional (affordant) properties of the objects to-be-used in future studies.

Acamprosate: a prototypic neuromodulator in the treatment of alcohol dependence.

Alcoholism is one of the most prevalent substance dependence disorders in the world. Advances in research in the neurobiological mechanisms underlying alcohol dependence have identified specific neurotransmitter targets for the development of pharmacological treatments. Acamprosate, marketed under the brand name Campral, is an orally administered drug available by prescription in the U.S. and throughout much of the world for treating alcohol dependence. Its safety and efficacy have been demonstrated in numerous clinical trials worldwide. Here we provide an overview of acamprosate in the context of the neurobiological underpinnings of alcohol dependence. We propose that unlike previously available pharmacotherapies, acamprosate represents a prototypical neuromodulatory approach in the treatment of alcohol dependence. A neuromodulatory approach seeks to restore the disrupted changes in neurobiology resulting from chronic alcohol intake. We believe that a neuromodulatory approach will provide a heuristic framework for developing more effective pharmacotherapies for alcohol dependence.

The neurobiology, clinical efficacy and safety of acamprosate in the treatment of alcohol dependence.

IMPORTANCE TO THE FIELD: Acamprosate, marketed under the brand name Campral, (Forest Pharmaceuticals, Inc., Saint Louis, MO, USA; Merck Sante s.a.s., Lyon, France) is an orally administered drug approved in the US and throughout much of the world for treating alcohol dependence. Its safety and efficacy have been demonstrated in a number of clinical trials worldwide and as with all pharmacotherapies for alcoholism, it is used in conjunction with psychosocial interventions. AREAS COVERED IN THIS REVIEW: This article reviews the mechanism of action, clinical efficacy and safety of acamprosate in Phase I, II and III randomized controlled trials involving healthy and alcohol-dependent populations using published reports from 1984 to 2009. WHAT THE READER WILL GAIN: This review provides an update of the mechanism of action and the safety and efficacy profile of acamprosate. TAKE HOME MESSAGE: Acamprosate appears to act centrally to restore the normal activity of glutamatergic neurotransmission altered by chronic alcohol exposure. Acamprosate's excellent safety profile along with several pharmacokinetic and pharmacodynamic characteristics make it well suited for treating a broad population of alcohol-dependent patients.

Assessment of developmental milestones in rodents.

Developmental tests are used to characterize early markers of behavior for investigation of the neurobiology of these behaviors, and to assess the impact of early prenatal or postnatal insult. These perturbations may include pharmacological, environmental, and genetic manipulations. At birth the rat is capable of some specific activities, but its movements are uncoordinated and seemingly random, its tactile sensitivity is not fully developed, and its ear canals and eyes remain closed until several days after birth. Postnatal development consists mainly of the continuation of processes begun earlier. This unit presents protocols for the most commonly used animal tests of developmental reflexology, including negative geotaxis, cliff avoidance, placing responses, tactile and acoustic startle responses, surface and air righting reflexes, crossed extensor reflex, rooting reflex, grasp reflex, bar holding, and horizontal and vertical screen tests.