Browsing by Author "Schalomon, Melike"
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- ItemA novel method of drug administration to multiple zebrafish (Danio rerio) and the quantification of withdrawal(2014) Holcombe, Adam; Schalomon, Melike; Hamilton, TrevorAnxiety testing in zebrafish is often studied in combination with the application of pharmacological substances. In these studies, fish are routinely netted and transported between home aquaria and dosing tanks. In order to enhance the ease of compound administration, a novel method for transferring fish between tanks for drug administration was developed. Inserts that are designed for spawning were used to transfer groups of fish into the drug solution, allowing accurate dosing of all fish in the group. This increases the precision and efficiency of dosing, which becomes very important in long schedules of repeated drug administration. We implemented this procedure for use in a study examining the behavior of zebrafish in the light/dark test after administering ethanol with differing 21 day schedules. In fish exposed to daily-moderate amounts of alcohol there was a significant difference in location preference after 2 days of withdrawal when compared to the control group. However, a significant difference in location preference in a group exposed to weekly-binge administration was not observed. This protocol can be generalized for use with all types of compounds that are water-soluble and may be used in any situation when the behavior of fish during or after long schedules of drug administration is being examined. The light/dark test is also a valuable method of assessing withdrawal-induced changes in anxiety.
- ItemEffects of acute exposure to cannabinoids on zebrafish behaviour(2018) Pinder, Lyndsay; Schalomon, Melike; Hamilton, TrevorCannabinoid therapeutic potential is increasingly studied using animal models. Zebrafish (Danio rerio) are a useful model organism because cannabinoids interrupt zebrafish endocannabinoid systems similarly to how human endocannabinoid systems are interrupted (Oltrabella, Melgoza, Nguyen, & Guo, 2017). Zebrafish also demonstrate observable behavioural changes when under stress. Zebrafish behaviour in response to multiple doses of the cannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), will be recorded. Finally, dose response curves for the effects of THC and CBD on behaviour during the light/dark preference and novel tank dive tests will be established. Both of these tests are tests of anxiety displayed by individual zebrafish, and both are linked to predator avoidance behaviours. Previous research has suggested that THC and CBD may have anxiolytic effects (Stewart, Kaleuff, 2013; Nazario et al., 2015), implying these cannabinoids may alter zebrafish fish behaviour during the tests, as compared to zebrafish in the control condition.
- ItemEpisodic-like memory in zebrafish(2016) Hamilton, Trevor; Myggland, Allison; Duperreault, Erika; May, Zacnicte; Gallup, Joshua; Powell, Russell A.; Schalomon, Melike; Digweed, ShannonEpisodic-like memory tests often aid in determining an animal's ability to recall the what, where, and which (context) of an event. To date, this type of memory has been demonstrated in humans, wild chacma baboons, corvids (Scrub jays), humming birds, mice, rats, Yucatan minipigs, and cuttlefish. The potential for this type of memory in zebrafish remains unexplored even though they are quickly becoming an essential model organism for the study of a variety of human cognitive and mental disorders. Here we explore the episodic-like capabilities of zebrafish ( Danio rerio) in a previously established mammalian memory paradigm. We demonstrate that when zebrafish were presented with a familiar object in a familiar context but a novel location within that context, they spend more time in the novel quadrant. Thus, zebrafish display episodic-like memory as they remember what object they saw, where they saw it (quadrant location), and on which occasion (yellow or blue walls) it was presented.
- ItemEstablishing zebrafish as a model to study the anxiolytic effects of scopolamine(2017) Hamilton, Trevor; Morrill, Adam; Lucas, Kayla; Gallup, Joshua; Harris, Megan; Healey, Meghan; Pitman, Taylor; Schalomon, Melike; Digweed, Shannon; Tresguerres, MartinScopolamine (hyoscine) is a muscarinic acetylcholine receptor antagonist that has traditionally been used to treat motion sickness in humans. However, studies investigating depressed and bipolar populations have found that scopolamine is also effective at reducing depression and anxiety symptoms. The potential anxiety-reducing (anxiolytic) effects of scopolamine could have great clinical implications for humans; however, rats and mice administered scopolamine showed increased anxiety in standard behavioural tests. This is in direct contrast to findings in humans, and complicates studies to elucidate the specific mechanisms of scopolamine action. The aim of this study was to assess the suitability of zebrafish as a model system to test anxiety-like compounds using scopolamine. Similar to humans, scopolamine acted as an anxiolytic in individual behavioural tests (novel approach test and novel tank diving test). The anxiolytic effect of scopolamine was dose dependent and biphasic, reaching maximum effect at 800 µM. Scopolamine (800 µM) also had an anxiolytic effect in a group behavioural test, as it significantly decreased their tendency to shoal. These results establish zebrafish as a model organism for studying the anxiolytic effects of scopolamine, its mechanisms of action and side effects.
- ItemExamining behavioural test sensitivity and locomotor proxies of anxiety-like behaviour in zebrafish(2023) Johnson, Andrea; Loh, Erica; Slessor, Jordan; Verbitsky, Ryan; Franczak, Brian C.; Schalomon, Melike; Hamilton, TrevorThis study assessed the sensitivity of four anxiety-like behaviour paradigms in zebrafish: the novel tank dive test, shoaling test, light/dark test, and the less common shoal with novel object test. A second goal was to measure the extent to which the main effect measures are related to locomotor behaviours to determine whether swimming velocity and freezing (immobility) are indicative of anxiety-like behaviour. Using the well-established anxiolytic, chlordiazepoxide, we found the novel tank dive to be most sensitive followed by the shoaling test. The light/dark test and shoaling plus novel object test were the least sensitive. A principal component analysis and a correlational analysis also showed the locomotor variables, velocity and immobility, did not predict the anxiety-like behaviours across all behaviour tests.
- ItemObject recognition memory in zebrafish(2016) May, Zacnicte; Morrill, Adam; Holcombe, Adam; Johnston, Travis; Gallup, Joshua; Fouad, Karim; Schalomon, Melike; Hamilton, TrevorThe novel object recognition, or novel-object preference (NOP) test is employed to assess recognition memory in a variety of organisms. The subject is exposed to two identical objects, then after a delay, it is placed back in the original environment containing one of the original objects and a novel object. If the subject spends more time exploring one object, this can be interpreted as memory retention. To date, this test has not been fully explored in zebrafish (Danio rerio). Zebrafish possess recognition memory for simple 2- and 3-dimensional geometrical shapes, yet it is unknown if this translates to complex 3-dimensional objects. In this study we evaluated recognition memory in zebrafish using complex objects of different sizes. Contrary to rodents, zebrafish preferentially explored familiar over novel objects. Familiarity preference disappeared after delays of 5 mins. Leopard danios, another strain of D. rerio, also preferred the familiar object after a 1 min delay. Object preference could be re-established in zebra danios by administration of nicotine tartrate salt (50 mg/L) prior to stimuli presentation, suggesting a memory-enhancing effect of nicotine. Additionally, exploration biases were present only when the objects were of intermediate size (2 × 5 cm). Our results demonstrate zebra and leopard danios have recognition memory, and that low nicotine doses can improve this memory type in zebra danios. However, exploration biases, from which memory is inferred, depend on object size. These findings suggest zebrafish ecology might influence object preference, as zebrafish neophobia could reflect natural anti-predatory behaviour.
- ItemPreferences for achromatic horizontal, vertical, and square patterns in zebrafish (Danio rerio)(2017) Rimstad, Lisa; Holcombe, Adam; Pope, Alicia; Hamilton, Trevor; Schalomon, MelikeThe zebrafish (Danio rerio) is gaining popularity as a laboratory organism and is used to model many human diseases. Many behavioural measures of locomotion and cognition have been developed that involve the processing of visual stimuli. However, the innate preference for vertical and horizontal stripes in zebrafish is unknown. We tested the preference of adult zebrafish for three achromatic patterns (vertical stripes, horizontal stripes, and squares) at three different size conditions (1, 5, and 10 mm). Each animal was tested once in a rectangular arena, which had a different pattern of the same size condition on the walls of either half of the arena. We show that zebrafish have differential preferences for patterned stimuli at each of the three size conditions. These results suggest that zebrafish have naïve preferences that should be carefully considered when testing zebrafish in paradigms using visual stimuli.
- ItemReversed scototaxis during withdrawal after daily- moderate, but not weekly-binge, administration of ethanol in zebrafish(2013) Holcombe, Adam; Howorko, Adam; Powell, Russell A.; Schalomon, Melike; Hamilton, TrevorAlcohol abuse can lead to severe psychological and physiological damage. Little is known, however, about the relative impact of a small, daily dose of alcohol (daily-moderate schedule) versus a large, once per week dose (weekly-binge schedule). In this study, we examined the effect of each of these schedules on behavioural measures of anxiety in zebrafish (Danio rerio). Adult wild-type zebrafish were administered either 0.2% ethanol on a daily-moderate schedule or 1.4% ethanol on a weekly-binge schedule for a period of 21 days, and then tested for scototaxis (preference for darkness) during withdrawal. Compared to a control group with no alcohol exposure, the daily-moderate group spent significantly more time on the light side of the arena (indicative of decreased anxiety) on day two of withdrawal, but not day 9 of withdrawal. The weekly-binge group was not significantly different from the control group on either day of withdrawal and showed no preference for either the light or dark zones. Our results indicate that even a small dose of alcohol on a daily basis can cause significant, though reversible, changes in behaviour.
- ItemSexuality in a community based sample of adults with autism spectrum disorder(2011) Gilmour, Laura; Schalomon, Melike; Smith, VeronicaFew studies have examined the sexual attitudes and behaviours of individuals with high functioning autism spectrum disorders (ASDs) living in community settings. A total of 82 (55 female and 17 male) adults with autism were contrasted with 282 members of the general population on their responses to an online survey of sexual knowledge and experiences. Findings revealed that individuals with ASD display an interest in sex and engage in sexual behaviours and showed no significant differences in breadth and strength of sexual behaviours and comprehension of sexual language when contrasted with non-ASD participants. However, despite these similarities, a higher rate of asexuality was found among individuals with ASD. In addition, the results of the current study indicated that females with ASD show a significantly lower degree of heterosexuality when compared to males with ASD. The results also suggested a higher degree of homosexuality among females with ASD although this effect did not reach significance.
- ItemSexuality in a community-based sample of adults with autism spectrum disorder(2012) Gilmour, Laura; Schalomon, Melike; Smith, VeronicaThe current study sampled 82 adults with ASD and normal intelligence (nfemale=55, nmale=27) and 282 members of the general population. Research was conducted via online survey. We hypothesized that brain masculinization would result in a higher rate of homosexual behaviours and interests among females with ASD and a lower rate among males. We also explored the hypothesis that general patterns of sexual behaviour would be altered by ASD, and that the number of partners and frequency of sexual activity among individuals with ASD would differ from that in the general population.
- ItemThe effect of chronic lysergic acid diethylamide exposure and withdrawal in zebrafish(2020) Kumar, Jessica; Schalomon, MelikeZebrafish (Danio rerio) are an excellent model for neuroscience research due to the similarities in neurochemistry they share with humans. Zebrafish are a good model for anxiety research as they are highly anxious prey species. In addition, cortisol is the primary stress hormone in both humans and zebrafish. This enables researchers to study the relationship between neurotransmitter systems and hallucinogenic drugs. There has been little research into hallucinogens due to their reputation as drugs of abuse and focusing on their benefits is a recent development. The few studies conducted on acute lysergic acid diethylamide (LSD) exposure in zebrafish has shown a significant anxiolytic effects. The current study involves chronic exposure of zebrafish to LSD. Subjects will be randomly assigned to a low or high dose of either 100 μg/L or 250 μg/L for 11 days and behaviour in the open field test will be assessed on the 11th and 18th day. Based on past research, since fish have experienced a decrease in anxiety when exposed to LSD, the withdrawal will elicit a rebound effect. This research will increase understanding of hallucinogens and their potential therapeutic application in disorders such as anxiety. Future research should address the nature of chronic exposure of lower doses as well as the effect hallucinogens have on treating addiction disorders.
- ItemThe effects of the H1 antagonist chlorpheniramine on anxiety in zebrafish(2017) Heritage, Susan; Schalomon, MelikeZebrafish (Danio rerio) have recently emerged as an excellent model organism to study the neurological basis of anxiety disorders. They display robust behavioural responses to external stimuli and possess all of the main vertebrate neurotransmitters. Research in rats has demonstrated that the histaminergic system plays a role in anxiety, possibly by interacting with other monoamines such as serotonin and dopamine. In zebrafish, however, the histaminergic system is not well characterized, so it is of interest to assess the role of histamine on anxiety in zebrafish. Chlorpheniramine, a histamine antagonist that has been tested multiple times in rodents and shown to decrease anxiety, was administered to fish with the expectation that we would observe similar anxiolytic effects in zebrafish. Chlorpheniramine was administered through immersion for ten minutes at two doses (20mg/L and 25mg/L), and zebrafish were tested using the shoaling test, which is a measure of anxiety based on the tendency of fish to form more cohesive shoals when anxious. We found that chlorpheniramine did not produce a significant anxiolytic effect at either dose; however previous research in our lab suggests that the 20mg/L dose reduces anxiety in the novel tank diving test. Further research using different doses and tests or other histamine antagonists should be conducted for a more thorough understanding of the histaminergic system in zebrafish.