T-maze Assay Research Articles

Deterrent Effects of Clary Sage Oil and Two Major Constituents against Drosophila suzukii (Diptera: Drosophilidae).

Drosophila suzukii (Diptera: Drosophilidae), spotted-wing drosophila, poses a significant threat to soft-skinned fruit crops in the Americas, Europe, Africa, and Oceania, as well as in Asia. The application of chemical insecticides is the primary control strategy for D. suzukii; however, resistance has developed with the indiscriminate use of chemical insecticides. Essential oils, considered potential alternatives to pesticidal strategies, exhibit potent toxic and sublethal behavioral effects against numerous pests, including D. suzukii. Clary sage oil repels a variety of agricultural and household pests; however, whether it has a repellent effect against D. suzukii remains unknown. Here, we found that clary sage oil exhibited dose-dependent repellency against D. suzukii adults in a T-maze assay, a two-choice assay and a two-choice attraction assay. Also, clary sage oil showed a significant repellent effect against D. suzukii larvae. Next, we explored the chemical constituents of clary sage oil by GC-MS and identified two major constituents, linalyl acetate (40.03%) and linalool (23.02%). Furthermore, the behavioral assays of linalyl acetate and linalool showed that both compounds conferred comparable repellency against D. suzukii adults and larvae. Finally, we found clary sage oil, linalyl acetate, and linalool elicited EAG responses in D. suzukii, especially clary sage oil, suggesting the repellency was mediated by the olfactory system. These findings indicate that D. suzukii shows olfactory-based behavioral avoidance of clary sage oil, linalyl acetate, and linalool. Clary sage oil and its major constituents may be possible alternatives in the management of D. suzukii.

Antinociceptive effects of α2/α3-subtype selective GABAA receptor positive allosteric modulators KRM-II-81 and NS16085 in rats: behavioral specificity.

Recent studies suggest that amongst the GABAA receptor subtype heterogeneity, α2/α3 subunits of GABAA receptors mediate pain processing. Therefore, α2/α3-subtype selective GABAA receptor positive allosteric modulators (PAMs) may be candidate analgesics. Antinociceptive effects of α2/α3-subtype selective GABAA receptor PAMs have been reported, but the behavioral effects of these compounds have not been systematically evaluated. This study examined the behavioral effects of two α2/α3 subtype-selective GABAA receptor PAMs, KRM-II-81 and NS16085, in male rats. The antinociceptive effects of KRM-II-81 and NS16085 were examined using rat models of inflammatory (complete Freund's adjuvant) and neuropathic pain (chronic constriction injury). The effect of KRM-II-81 on affective pain was measured using the place escape/avoidance paradigm (PEAP). Rate-response of food-maintained operant responding, horizontal wire test, and the spontaneous alternation T-maze, were assessed to study the side-effect profiles of KRM-II-81 and NS16085. The benzodiazepine midazolam was used as a comparator in these studies. KRM-II-81 and NS16085 attenuated mechanical allodynia but not thermal hyperalgesia in both pain states, and their effects were attenuated by the benzodiazepine receptor antagonist flumazenil. KRM-II-81 attenuated affective pain-related behavior in the PEAP test. In the operant responding procedure and horizontal wire test, only midazolam produced significant effects at the dose that produced maximal antinociception. In the T-maze assay, only midazolam significantly decreased the percentage of alternation at an antinociceptive dose. Thus, KRM-II-81 and NS16085 but not midazolam selectively produced antinociceptive effects. Collectively, these data suggest that α2/α3-subtype selective GABAA PAMs could be a novel class of analgesics and warrant further investigation. Significance Statement This study demonstrates that α2/α3-subtype selective GABAA PAMs KRM-II-81 and NS16085 produce selective antinociceptive effects devoid of sedation, myorelaxation, cognitive impairment in two rat models of persistent pain. Unlikely classical benzodiazepines, this study supports the development of α2/α3-subtype selective GABAA PAMs as safe and novel analgesics for pain management.

The Tetrahymena Paradigm: Genetic Insights and Ecotoxicity Assessment

Tetrahymena, a ciliated protozoan, thrives in freshwater habitats across diverse climates. Its importance as a genetic model organism lies in its cellular complexity, with cells comparable to human cells and a genome size between yeast and human. Tetrahymena’s germline genome undergoes unique chromosome breakage and DNA elimination, shedding light on genome rearrangement mechanisms. In 2020, the macronuclear genome was fully sequenced, offering improved insights into chromosome structure and gene models. Tetrahymena’s molecular tools enable gene characterization, knockouts, and overexpression. Beyond genetics, Tetrahymena serves as an ecotoxicity model, particularly Tetrahymena pyriformis. Changes in its morphology, food vacuole formation, and contractile vacuole response serve as toxicity indicators. Tetrahymena’s unique nuclear dimorphism (micronucleus and macronucleus) adds depth to ecotoxicological research. Additionally, Tetrahymena’s behavioral endpoints, including chemotaxis, phagocytosis, and motility, offer sensitive toxicity markers. Researchers have developed a T-maze toxotactic assay, a quick tool for studying Tetrahymena’s behavioral responses to different chemicals. Tetrahymena’s phagocytosis and motility are influenced by exposure to toxicants, reflecting changes in ion channels. Tetrahymena’s rapid movement makes it ideal for studying motility alterations caused by toxic substances. AI-driven tools enhance Tetrahymena behavior studies, allowing for behavior classification, feature extraction, and predictive modeling. This interdisciplinary approach aids in understanding Tetrahymena’s intricate behaviors, offering potential applications in gene discovery and pharmacological interventions. In conclusion, Tetrahymena stands as an invaluable model organism for genetic and ecotoxicological research. Its advantages, including genetic tractability and behavioral sensitivity, contribute to our understanding of fundamental biological processes and chemical safety assessment, with AI playing a growing role in advancing this field.

Neuroprotective Effect of Ethanolic Extract of Scoparia dulcis on Acrylamide-Induced Neurotoxicity in Zebrafish Model.

All herbal medicines are reported to be safe and have better results in curing disabilities. Scoparia dulcis is known for its anti-inflammatory and antioxidant properties. This study has been executed to explore the neuroprotective effects of ethanolic extract of Scoparia dulcis (EESD) against acrylamide using adult zebrafish. The experimental period was 72h. After fixing the optimum acrylamide concentration and EESD, the healthy adult fish were grouped into control, induction, and treatment. During the experimental period, behavioural changes such as memory and locomotion were observed in control and experimental groups using the T-maze experiment. After 72h, the neuronal tissues were isolated from the grouped fishes and analysed for various biochemical and enzymatic assays. The mRNA of the HSP-70 gene in control and experimental groups was expressed using RT-PCR. The optimum dosages for acrylamide and EESD were found to be 0.75mM and 20µg/mL, respectively. Memory improvement was observed in S. dulcis-treated fish, compared to the acrylamide-treated group using the T-maze assay. The extract reduced the toxicity induced by acrylamide from the various biochemical and histopathological parameters. The result shows the potential neuroprotective effects of ethanolic extract of Scoparia dulcis (EESD) against acrylamide-induced neurotoxicity in adult zebrafish. Therefore, Scoparia dulcis is a potent neuroprotective agent.

Long-term sevoflurane exposure resulted in temporary rather than lasting cognitive impairment in Drosophila

Sevoflurane is the primary inhaled anesthetic used in pediatric surgery. It has been the focus of research since animal models studies found that it was neurotoxic to the developing brain two decades ago. However, whether pediatric general anesthesia can lead to permanent cognitive deficits remained a subject of heated debate. Therefore, our study aims to determine the lifetime neurotoxicity of early long-time sevoflurane exposure using a short-life-cycle animal model, Drosophila melanogaster. To investigate this question, we measured the lifetime changes of two-day-old flies' learning and memory abilities after anesthesia with 3 % sevoflurane for 6 h by the T-maze memory assay. We evaluated the apoptosis, levels of ATP and ROS, and related genes in the fly head. Our results suggest that 6 h 3 % sevoflurane exposure at a young age can only induce transient neuroapoptosis and cognitive deficits around the first week after anesthesia. But this brain damage recedes with time and vanishes in late life. We also found that the mRNA level of caspases and Bcl-2, ROS level, and ATP level increased during this temporary neuroapoptosis process. And mRNA levels of antioxidants, such as SOD2 and CAT, increased and decreased simultaneously with the rise and fall of the ROS level, indicating a possible contribution to the recovery from the sevoflurane impairment. In conclusion, our results suggest that one early prolonged sevoflurane-based general anesthesia can induce neuroapoptosis and learning and memory deficit transiently but not permanently in Drosophila.

Effects of Morphine on Gp120-induced Neuroinflammation Under Immunocompetent Vs. Immunodeficient Conditions.

HIV-associated neurocognitive disorder (HAND) is a common complication of HIV infection, whose development is known to be facilitated by inflammation and exacerbated by morphine. Previously, using the gp120 transgenic (tg) mouse model in combination with LP-BM5 (a murine retrovirus that can cause systemic immunodeficiency in susceptible mouse strains) we demonstrated differential gp120-associated central nervous system (CNS) neuroinflammatory responses under immunocompetent (-LP-BM5) vs. immunocompromised (+LP-BM5) conditions. Here, we further investigated the effects of morphine on gp120-associated neuroinflammatory response within the hippocampus under differential immune status. First, we confirmed that morphine treatment (2 × 25mg pellets) did not significantly affect the development of immunodeficiency induced by LP-BM5 and all brain regions examined (hippocampus, striatum, and frontal lobe) had detectable LP-BM5 viral gag genes. Morphine notably reduced the performance of gp120tg+ mice in the alteration T-maze assay when 2-minute retention was used, regardless of LP-BM5 treatment. Morphine further enhanced GFAP expression in gp120tg+ mice regardless of host immune status, while promoted CD11b expression only in immunocompetent mice, regardless of gp120tg expression. In immunocompetent gp120tg+ mice, morphine increased the RNA expression of CCL2, CCL5, CXCL10, IL-12p40, and IFNβ; while under the immunodeficient condition, morphine downregulated the expression of CCL2, CCL5, CXCL10, IL-12p40, and IL-1β. Further, expression of TNFα and IFNγ were enhanced by morphine regardless of host immune status. Altogether, our results suggest that the effects of morphine are complex and dependent on the immune status of the host, and host immune status-specific, targeted anti-neuroinflammatory strategies are required for effective treatment of HAND.

The Role of Antennae in Heat Detection and Feeding Behavior in the Bed Bug (Hemiptera: Cimicidae).

The common bed bug (Cimex lectularius L.) is an obligate hematophagous ectoparasite that has significant impacts on human health and well-being. All life stages of bed bugs (except eggs) feed solely on blood, which is required to molt and reproduce. Bed bugs use multiple cues to locate their hosts, including heat, CO2, and body odors. Of these cues, detection of heat appears limited to a short distance of <3 cm. However, it remains unclear if bed bugs can detect radiant heat, what structure(s) are responsible for heat detection, and if heat detection via the antennae is required for feeding. In this study, bed bug response to radiant heat was evaluated using the two-choice T-maze assay with the heat source either in contact with the surface (i.e., conduction) or not in contact (i.e., radiation) in nonantennectomized bed bugs. Further, we systematically ablated the bed bug's antennal segments (distal tip, first segment, and all four segments) and assessed their responses to heat and feeding in a unique two-choice T-maze assay and individual feeding assays, respectively. Our two-choice assays with contact to or no contact with the surface indicated that bed bugs cannot detect radiant heat. Later, we found that the distal tip of the terminal antennal segment is responsible for orientation toward a heat source. However, >50% of the bed bugs fed even when the entire antenna was removed, suggesting redundancy in sensory cues that drive feeding. These results will be used to better understand the role heat plays in bed bug host attraction and design of traps.

Effects of Morphine on Behavioral and CNS Inflammatory Responses in GP120 Mice Under Immunocompetent vs. Immunodeficient Conditions

Abstract HIV-associated neurocognitive disorder is a common complication of HIV infection, whose development is known to be facilitated by inflammation and exacerbated by morphine. In this study, we infected HIV gp120tg mice with LP-BM5 (a murine retrovirus that can cause systemic immunodeficiency in susceptible mouse strains) to examine morphine’s effect on gp120 in both immunocompetent and immunodeficient conditions. Specifically, we examined the expression of a series of inflammation-related molecules in the brain via qRT-PCR as well as the animals’ learning/memory function using spontaneous alternation T-maze. Morphine treatment (2×25mg pellets) did not significantly affect the development of immunodeficiency induced by LP-BM5 and all brain regions examined (hippocampus, striatum, and frontal lobe) had detectable LP-BM5 viral gag genes. Morphine notably reduced the performance of gp120tg+ mice in the T-maze assay when 2-minute retention was used, regardless of LP-BM5 treatment. Without LP-BM5 treatment, morphine increased hippocampal expression of CCL2, CCL5, CXCL10, IL-12 p40, TNFα, and IFNγ, while it decreased the expression of IL-6, arginase-1, IFNα and IFNβ. For mice who were subjected to LP-BM5 treatment, hippocampal expression of CCL2, CCL5, CXCL10, IL-12p40, and IL-1β were decreased by morphine, while CCL4, TNFα, IFNγ, iNOS, arginase-1 and IFNβ were increased by morphine. Further, expression of the mu opioid receptor was upregulated by morphine without LP-BM5, yet down-regulated by morphine with LP-BM5 treatment. Altogether, the effects of morphine are complex and dependent on the immune status of the host, which will be further elucidated in the future studies. (Supported by NIH/NIDA R21DA044886 (PI, Cao))

Phototactic T-maze Behavioral Assay for Comparing the Functionality of Color-sensitive Photoreceptor Subtypes in the Drosophila Visual System

The Drosophila retina contains light-sensitive photoreceptors (R cells) with distinct spectral sensitivities that allow them to distinguish light by its spectral composition. R7 and R8 photoreceptors are important for color vision, and can be further classified into pale (p) or yellow (y) subtypes depending on the rhodopsin expressed. While both R7y and R7p are sensitive to UV light, R8y and R8p detect light in the green and blue spectrum, respectively. The ability of R7 and R8 photoreceptors to distinguish different spectral sensitivities and the natural preference for Drosophila towards light sources (phototaxis), allow for the development of a phototactic T-maze assay that compares the functionality of different R7 and R8 subtypes. A "UV vs. blue" choice can compare the functionalities of R7p and R8p photoreceptors, while a "UV vs. green" choice can compare the functionalities of R7y and R8y photoreceptors. Additionally, a "blue vs. green" choice could be used to compare R8p and R8y photoreceptors, while a "dark vs. light" choice could be used to determine overall vision functionality. Although electrophysiological recordings and calcium imaging have been used to examine functionality of R7 and R8 photoreceptors, these approaches require expensive equipment and are technically challenging. The phototactic T-maze assay we present here is a robust, straight-forward and an inexpensive method to study genetic and developmental factors that contribute to the individual functionality of R7 and R8 photoreceptors, and is especially useful when performing large-scale genetic screens.

The effect of copper on behaviour, memory, and associative learning ability of zebrafish (Danio rerio)

Copper is an essential element in many biological processes, but may exert toxic effects at levels surplus to metabolic requirements. Herein we assess the effect of copper on zebrafish behaviour using two assays, namely the novel tank diving test and a T-maze test with food reward. Novel tank diving tests were conducted on days 0, 4, and 10 of a 10 day Cu exposure (at concentrations of 0.77 μM (25% of the 240 h LC50) and 1.52 μM (50% of the 240 h LC50) to assess the alterations of behavioural responses in repeating novel tank diving assays and the effect of Cu on these patterns. Results demonstrate habituation to novelty, which is an indicator of spatial memory. Copper exposure had no effect on the latency of entry into the upper zones of the tank, nor on the total time spent therein, but did cause a greater number of freezing bouts in comparison to the control group. Additionally, Cu exposure had no effect on the habituation responses of zebrafish. Using the T-maze assay, we tested the effect of prior exposure to Cu for 10 days on subsequent behavioural trainings. The T-maze protocol was based on associative learning, where a visual stimulus (colour) was linked with a natural stimulus (food). Results of the control group showed that zebrafish are able to perform associative learning tasks. Moreover, Cu was found to negatively affect the associative learning capabilities. Specifically, while zebrafish in the control group achieved a significant number of correct choices (leading to food reward) throughout the T-maze training, such a trend was not observed for Cu exposed fish. Thus at the exposure concentrations and exposure times considered herein, Cu has no determinative impact on instinctual behavioural responses of zebrafish in repeated novel tank diving assays but does limit the associative learning capabilities.

A novel T-maze assay to evaluate chemical irritants on Lumbricus terrestris

Earthworms have a profound effect on the soil they inhabit, but our current understanding of the chemical factors and molecular mechanisms that attract or repel earthworms from a specific area of soil is limited. In this study, we developed a soil T-maze assay allowing for the examination of earthworm behavioral responses to repellent chemicals. This tests earthworms individually, and thus the potential confounds of worms being influenced by conspecifics signals are avoided. Canadian nightcrawlers (Lumbricus terrestris) can detect the canonical Transient Receptor Potential Ankyrin 1 (TRPA1) agonist, allyl isothiocyanate (AITC), but not the canonical Transient Receptor Potential Vanilloid 1 (TRPV1) agonist capsaicin. In the T-maze assay L. terrestris avoided TRPA1 activators AITC, cinnamaldehyde and menthol in a dosage dependent manner. The single subject T-maze assay is a useful tool to study the avoidance of earthworms to chemical compounds and provides behavioral evidence for a TRPA1 ortholog in L. terrestris.

Comparative Antennal and Behavioral Responses of Summer and Winter Morph Drosophila suzukii (Diptera: Drosophilidae) to Ecologically Relevant Volatiles.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a devastating global pest of berry crops and cherries. Little is understood about its biology during the winter in northern temperate regions, including potential resources that it may utilize during this period. In this study, olfactory and behavioral responses of female D. suzukii to six volatiles (methionol, acetic acid, linalool, bornyl acetate, isoamyl acetate, and geosmin) were evaluated separately for electroantennogram (EAG) and behavioral assays between summer and winter morphs. Results of EAG indicated that isoamyl acetate, acetic acid, and geosmin elicited significantly higher olfactory responses from the antennae of female summer morph D. suzukii compared with those of female winter morph D. suzukii. Winter morph D. suzukii showed reduced antennal response to the volatiles overall. Geosmin and bornyl acetate elicited significantly different behavioral responses from the two morphs in no-choice laboratory behavioral assays. T-maze behavioral assays with geosmin further revealed that summer morphs had a significant aversion, while winter morphs showed no significant aversion to geosmin. Overall, we demonstrate that responses of the two seasonally induced morphs to environmental stimuli are different, and future studies are justified to further understand how these physiological and behavioral differences may contribute to improved pest management of D. suzukii.

Feel the heat: activation, orientation and feeding responses of bed bugs to targets at different temperatures.

Host location in bed bugs is poorly understood. Of the primary host-associated cues known to attract bed bugs - CO2, odors, heat - heat has received little attention as an independent stimulus. We evaluated the effects of target temperatures ranging from 23 to 48°C on bed bug activation, orientation and feeding. Activation and orientation responses were assessed using a heated target in a circular arena. All targets heated above ambient temperature activated bed bugs (initiated movement) and elicited oriented movement toward the target, with higher temperatures generally resulting in faster activation and orientation. The distance over which bed bugs could orient toward a heat source was measured using a 2-choice T-maze assay. Positive thermotaxis was limited to distances <3 cm. Bed bug feeding responses on an artificial feeding system increased with feeder temperature up to 38 and 43°C, and declined precipitously at 48°C. In addition, bed bugs responded to the relative difference between ambient and feeder temperatures. These results highlight the wide range of temperatures that elicit activation, orientation and feeding responses in bed bugs. In contrast, the ability of bed bugs to correctly orient towards a heated target, independently of other cues, is limited to very short distances (<3 cm). Finally, bed bug feeding is shown to be relative to ambient temperature, not an absolute response to feeder blood temperature.

Directional and color preference in adult zebrafish: Implications in behavioral and learning assays in neurotoxicology studies.

The zebrafish (Danio rerio) is a useful vertebrate model organism for neurological studies. While a number of behavior and learning assays are recently reported in the literature for zebrafish, many of these assays are still being refined. The initial purpose of this study was to apply a published T-maze assay for adult zebrafish that measures how quickly an organism can discriminate between different color stimuli after receiving reinforcement to measure learning in a study investigating the later life impacts of developmental Pb exposure. The original results were inconclusive as the control group showed a directional and color preference. To assess directional preference further, a three-chambered testing apparatus was constructed and rotated in several directions. The directional preference observed in males was alleviated by rotating the arms pointing west and east. In addition, color preference was investigated using all combinations of five different colors (orange, yellow, green, blue and purple). With directional preference alleviated results showed that both male and female zebrafish preferred colors of shorter wavelengths. An additional experiment tested changes in color preference due to developmental exposure to Pb in adult male zebrafish. Results revealed that Pb-exposed males gained and lost certain color preferences compared to control males and the preference for short wavelengths was decreased. Overall, these results show that consideration and pretesting should be completed before applying behavioral and learning assays involving adult zebrafish to avoid innate preferences and confounding changes in neurotoxicology studies and that developmental Pb exposure alters color preferences in adult male zebrafish.

Touchscreen tasks in mice to demonstrate differences between hippocampal and striatal functions

In mammals, hippocampal and striatal regions are engaged in separable cognitive processes usually assessed through species-specific paradigms. To reconcile cognitive testing among species, translational advantages of the touchscreen-based automated method have been recently promoted. However, it remains undetermined whether similar neural substrates would be involved in such behavioral tasks both in humans and rodents. To address this question, the effects of hippocampal or dorso-striatal fiber-sparing lesions were first assessed in mice through a battery of tasks (experiment A) comprising the acquisition of two touchscreen paradigms, the Paired Associates Learning (dPAL) and Visuo-Motor Conditional Learning (VMCL) tasks, and a more classical T-maze alternation task. Additionally, we sought to determine whether post-acquisition hippocampal lesions would alter memory retrieval in the dPAL task (experiment B). Pre-training lesions of dorsal striatum caused major impairments in all paradigms. In contrast, pre-training hippocampal lesions disrupted the performance of animals trained in the T-maze assay, but spared the acquisition in touchscreen tasks. Nonetheless, post-training hippocampal lesions severely impacted the recall of the previously learned dPAL task. Altogether, our data show that, after having demonstrated their potential in genetically modified mice, touchscreens also reveal perfectly adapted to taxing functional implications of brain structures in mice by means of lesion approaches. Unlike its human counterpart requiring an intact hippocampus, the acquisition of the dPAL task requires the integrity of the dorsal striatum in mice. The hippocampus only later intervenes, when acquired information needs to be retrieved. Touchscreen assays may therefore be suited to study striatal- or hippocampal-dependent forms of learnings in mice.

THE USE OF SELECTIVE SPHINGOSINE-1-PHOSPHATE RECEPTOR 5 AGONISTS FOR THE TREATMENT OF NEURODEGENERATIVE DISORDERS SUCH AS ALZHEIMER'S DISEASE AND LYSOSOMAL STORAGE DISEASES SUCH AS NIEMANN-PICK C DISEASE

Sphingosine-1-phosphate (S1P) plays an important role as a regulator of signal transduction, cellular plasticity, cell proliferation, membrane stability (e.g. BBB integrity), and modulates the ceramide-S1P homeostasis. S1P exerts its action through G protein-coupled receptors, such as S1P5. This receptor is preferentially expressed in the central nervous system (CNS), potentially limiting peripheral side-effects. Given the modulatory role on lipid homeostasis, BBB integrity, and cellular plasticity, it is expected that S1P5 agonism might be a beneficial treatment for neurodegenerative diseases such as Alzheimer's disease (AD). AbbVie has recently developed several selective S1P5 receptor agonists, including A-971432. A-971432 is a highly selective full hS1P5 receptor agonist (EC50 = 10 nM) with excellent PK properties such as good oral bio-availability (>60% in all species), half-life (7-9h), and brain penetration (B/P ∼0.2). This compound was used to test the hypothesis that selective S1P5 agonists will a) reduce CNS, but not peripheral lipid content, b) improve cognition, and c) change disease progression as assessed in a model mimicking key features of AD. A-971432 was examined in models of age-related cognitive decline including the spontaneous alternation T-maze assay in aged (12+ months) C57BL6J mice and Morris Water Maze (MWM) and the Object Recognition (ORT) task in aged (18+ months) Wistar rats. Chronic treatment (A≥3 7 days) in either T-maze (0.03 mg/kg - 3 mg/kg) or MWM/ORT (0.1 and 0.5 mg/kg) fully reversed the age-related cognitive deficits. The minimal efficacious dose in these models (set as >90% reversal in >80% of the animals) was 0.1 mg/kg with a plasma exposure of 40 ng/mL. Concomitantly, A-971432 (A≥3 0.1 mg/kg) normalizes the age-related CNS sphingolipid imbalance without affecting plasma levels. Finally, a single dose of A-971432 was examined in the murine model of Niemann Pick C disease (NPC). NPC is a lysosomal-endosomal storage (neurodegenerative) disorder resulting in massive lipid accumulation in the CNS. NPC subjects display AD-like pathology such as A β and Tau accumulation. A-971432 (1 mg/kg) was able to improve the behavioral phenotype (dystonia, motor impairment), promote survival, normalized CNS sphingolipid content, and normalized A β levels in the CSF. The data, together with the cognition and lipid modulation data indicate that S1P5 agonism provides an innovative mechanism for the treatment of neurodegenerative disorders such as AD and lysosomal storage disorders such as Niemann Pick C.

Water T-maze: A useful assay for determination of repetitive behaviors in mice

BackgroundRepetitive behavior is a term used to describe a wide variety of invariant and inappropriate behaviors that occur in many diverse conditions, including autism. It is necessary to utilize and/or design rodent behavioral assays that exploit individual types of repetitive behavior so that underlying pathology and therapeutic measures can be determined. A variety of high-throughput assays to investigate lower order repetitive behaviors are available for rodents, whereas, fewer assays are available to investigate higher order repetitive behaviors, such as perseverative behavior. BTBR T+tf/J (BTBR) mice, harbor behavioral deficits that share similarity to the core deficits found in autism, yet have not conclusively demonstrated deficits in conventional reversal learning tasks (i.e. Morris water maze (MWM), T-maze) which are typically used to examine perseverance. New methodBy combining elements of both the MWM and T-maze, we designed a water T-maze assay to determine if perseverative behavior could become perceptible in BTBR mice. ResultsWe found that BTBR mice show a significant impairment in reversal learning as compared to C57BL/6J (B6) mice in our water-T-maze reversal learning assay. Comparison of existing methodsOur water T-maze is sensitive, simple to perform, inexpensive and less time intensive than other tasks that can be used to measure higher order repetitive behaviors. ConclusionsOur findings suggest that our water T-maze assay is effective for determining perseverance, which is not readily revealed by using conventional methods.

A Conserved Dedicated Olfactory Circuit for Detecting Harmful Microbes in Drosophila

Flies, like all animals, need to find suitable and safe food. Because the principal food source for Drosophila melanogaster is yeast growing on fermenting fruit, flies need to distinguish fruit with safe yeast from yeast covered with toxic microbes. We identify a functionally segregated olfactory circuit in flies that is activated exclusively by geosmin. This microbial odorant constitutes an ecologically relevant stimulus that alerts flies to the presence of harmful microbes. Geosmin activates only a single class of sensory neurons expressing the olfactory receptor Or56a. These neurons target the DA2 glomerulus and connect to projection neurons that respond exclusively to geosmin. Activation of DA2 is sufficient and necessary for aversion, overrides input from other olfactory pathways, and inhibits positive chemotaxis, oviposition, and feeding. The geosmin detection system is a conserved feature in the genus Drosophila that provides flies with a sensitive, specific means of identifying unsuitable feeding and breeding sites.

Anesthetic action of volatile anesthetics by using Paramecium as a model

Although empirically well understood in their clinical administration, volatile anesthetics are not yet well comprehended in their mechanism studies. A major conundrum emerging from these studies is that there is no validated model to assess the presumed candidate sites of the anesthetics. We undertook this study to test the hypothesis that the single-celled Paramecium could be anesthetized and served as a model organism in the study of anesthetics. We assessed the motion of Paramecium cells with Expert Vision system and the chemoresponse of Paramecium cells with T-maze assays in the presence of four different volatile anesthetics, including isoflurane, sevoflurane, enflurane and ether. Each of those volatiles was dissolved in buffers to give drug concentrations equal to 0.8, 1.0, and 1.2 EC50, respectively, in clinical practice. We could see that after application of volatile anesthetics, the swimming of the Paramecium cells was accelerated and then suppressed, or even stopped eventually, and the index of the chemoresponse of the Paramecium cells (denoted as I ( che )) was decreased. All of the above impacts were found in a concentration-dependent fashion. The biphasic effects of the clinical concentrations of volatile anesthetics on Paramecium simulated the situation of high species in anesthesia, and the inhibition of the chemoresponse also indicated anesthetized. In conclusion, the findings in our studies suggested that the single-celled Paramecium could be anesthetized with clinical concentrations of volatile anesthetics and therefore be utilized as a model organism to study the mechanisms of volatile anesthetics.

An Increased Receptive Field of Olfactory Receptor Or43a in the Antennal Lobe of Drosophila Reduces Benzaldehyde-driven Avoidance Behavior

Most animals orient themselves in their environment through the perception of olfactory cues. In order to gain insight into the principles of olfactory processing in Drosophila, we misexpressed olfactory receptor Or43a in additional olfactory receptor neurons of the third antennal segment using enhancer trap line GH320. The behavioral response of GH320/UAS-or43a flies was changed upon benzaldehyde application. Using the T-maze assay, misexpressing flies performed a reduced avoidance reaction to benzaldehyde as compared with wild type. This reduction of avoidance could be mimicked in wild type flies by exposing them to a mixture of benzaldehyde and ethyl acetate. We therefore conclude that the application of benzaldehyde, an identified ligand of Or43a, resulted in activation of a number of glomeruli in transformed flies in addition to glomerulus DA4, which is the regular target of Or43a expressing neurons. Our results demonstrate the relevance of specific olfactory sensory input and subsequent processing in the antennal lobe for Drosophila behavior.