Browsing by Author "Thompson, MR"

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    5-HT1A Receptor
    (Springer-Verlag Berlin Heidelberg, 2010) Callaghan, PD; McGregor, IS; Thompson, MR
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    Adolescent rats find repeated Δ9-THC less aversive than adult rats but display greater residual cognitive deficits and changes in hippocampal protein expression following exposure
    (Springer Nature, 2007-06-20) Quinn, HR; Matsumoto, I; Callaghan, PD; Long, LE; Arnold, JC; Gunasekaran, N; Thompson, MR; Dawson, B; Mallet, PE; Kashem, MA; Matsda-Matsumoto, H; Iwazki, T; McGregor, IS
    The current study examined whether adolescent rats are more vulnerable than adult rats to the lasting adverse effects of cannabinoid exposure on brain and behavior. Male Wistar rats were repeatedly exposed to Δ9-tetrahydrocannabinol (Δ(9)-THC, 5 mg/kg i.p.) in a place-conditioning paradigm during either the adolescent (post-natal day 28+) or adult (post-natal day 60+) developmental stages. Adult rats avoided a Δ(9)-THC-paired environment after either four or eight pairings and this avoidance persisted for at least 16 days following the final Δ(9)-THC injection. In contrast, adolescent rats showed no significant place aversion. Adult Δ(9)-THC-treated rats produced more vocalizations than adolescent rats when handled during the intoxicated state, also suggesting greater drug-induced aversion. After a 10-15 day washout, both adult and adolescent Δ(9)-THC pretreated rats showed decreased social interaction, while onlyΔ (9)-THC pretreated adolescent rats showed significantly impaired object recognition memory. Seventeen days following their last Δ(9)-THC injection, rats were euthanised and hippocampal tissue processed using two-dimensional gel electrophoresis proteomics. There was no evidence of residual Δ(9)-THC being present in blood at this time. Proteomic analysis uncovered 27 proteins, many involved in regulating oxidative stress/mitochondrial functioning and cytoarchitecture, which were differentially expressed in adolescent Δ(9)-THC pretreated rats relative to adolescent controls. In adults, only 10 hippocampal proteins were differentially expressed in Δ(9)-THC compared to vehicle-pretreated controls. Overall these findings suggest that adolescent rats find repeated Δ(9)-THC exposure less aversive than adults, but that cannabinoid exposure causes greater lasting memory deficits and hippocampal alterations in adolescent than adult rats. © 2018 Springer Nature
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    Entactogen
    (Springer-Verlag Berlin Heidelberg, 2010) Callaghan, PD; McGregor, IS; Thompson, MR
    Entactogens are drugs, including MDMA (Ecstasy) and other MDxx structure compounds, that cause distinctive prosocial, emotional, and sensory effects in users. Most of them are substituted amphetamine compounds of the phenethylamine class. © 2010 Springer-Verlag Berlin Heidelberg
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    Herbal ecstasy
    (Springer-Verlag Berlin Heidelberg, 2010) Callaghan, PD; McGregor, IS; Thompson, MR
    Herbal ecstasy tablets, legally sold in many countries, usually contain the sympathomimetic herb Ephedra (Ma Huang) rather than the drug Ecstasy (MDMA). © 2010 Springer-Verlag Berlin Heidelberg
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    Methylenedioxymethamphetamine (MDMA)
    (Springer-Verlag Berlin Heidelberg, 2010) McGregor, IS; Thompson, MR; Callaghan, PD
    MDMA is a popular recreational drug that is renowned for its ability to produce euphoria and unique prosocial effects. It is the best known and most commonly used member of the family of phenethylamines (substitutes for amphetamines) that are sometimes known as entactogens, empathogens, or the MDxx class of drugs. MDMA has multiple neurochemical effects, the most prominent of which is to promote the release of serotonin via an action on the serotonin transporter (SERT). The prosocial effects of MDMA have recently been linked to the release of the neuropeptide oxytocin. High doses of MDMA can cause long-term depletion of serotonin in the brains of laboratory animals, but whether this also occurs in humans and whether this leads to associated psychopathology such as depression and cognitive impairment remains unclear. © 2010 Springer-Verlag Berlin Heidelberg
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    Oxytocin
    (Springer-Verlag Berlin Heidelberg, 2010) Callaghan, PD; McGregor, IS; Thompson, MR
    Oxytocin is a nine amino acid neuropeptide (nonapeptide), synthesized in the magnocellular neurosecretory cells of the hypothalamus and released both within the brain and from the posterior pituitary gland into the bloodstream. Oxytocin exerts peripheral actions that promote uterine contractions and the milk let-down reflex and is also increasingly recognized for its central effects that can lead to lasting changes in social behavior, mood and emotion in many mammalian species. Recent studies show that intranasal administration of oxytocin can modify social cognition, social memory, interpersonal behavior, and associated brain activation in human subjects. © 2010 Springer-Verlag Berlin Heidelberg
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    The psychopharmacology of MDMA
    (National Drug and Alcohol Research Centre, 2010) Thompson, MR; Callaghan, PD; McGregor, IS
    The psychoactive drug 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy, E, XTC) has an interesting history and a fascinating pharmacology. As discussed in Chapter 2, MDMA was first synthesised in 1912 and patented by the company E. Merck in 1914. Although commonly thought to have been designed as an appetite suppressant, the original patent bears no record of this and simply states that MDMA was deemed to contain primary constituents for therapeutically active compounds. The first reported pharmacological study involving MDMA occurred in 1927 although it was of limited scope and basic toxicology studies were not undertaken until the 1950s. Toxicology studies by Merck in 1952 provided little insight into the pharmacology of MDMA focusing on its effects on flies. Further studies at the University of Michigan, supported by the US Army, reported LD values for five different species, the lowest LD value being found in dogs, the highest in mice. As mentioned in Chapters 3 and 13, the first systematic use of MDMA was as an adjunct to insight-oriented psychotherapy4, with administration of MDMA producing an easily controllable altered state of consciousness with positive emotional and sensual overtones. The colloquial term for MDMA changed from “Empathy” as had been used by therapists in the 1970s, to “Ecstasy”, emphasising the drug’s euphoric effects. Heavy media attention in 1985 sensationalised Ecstasy’s euphoric effects. Despite this surge in popularity, the settings in which Ecstasy was used in the middle of the 1980’s typically involved two individuals or a small and intimate group5. This was soon to change with the emergence of the “rave” scene. In 1986, MDMA became a Schedule 1 drug in the USA, deemed to possess no recognised therapeutic value despite claims to the contrary. By the 1990s, ecstasy had became intrinsically linked to the club and rave culture, with use by groups of young people attending all-night dance parties where vigorous dancing occurred to highly repetitive and hypnotic “techno” music. This was thought to have originated in Europe in the late 1980s. Patterns of use in Australia largely mimicked those seen abroad, with dance parties, private parties and nightclubs listed as the most popular venues for use. Its popularity has continued to grow, and the contexts of use broadened. © 2010 NDARC
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    Social interaction test
    (Springer-Verlag Berlin Heidelberg, 2010) Callaghan, PD; McGregor, IS; Thompson, MR
    Two animals, typically rats or mice, are placed into an arena and their interactions, for example, investigation, following, and grooming, are recorded for a period of time, usually 5 to 10 min. Social behaviors such as following, adjacent lying, and anogenital sniffing are recorded by an observer or via automated image analysis. Many drugs modulate behavior on the social interaction test: benzodiazepines, MDMA, and oxytocin tend to increase social interaction while amphetamines, cannabinoids, NMDA antagonists, and withdrawal from various drugs of abuse tend to decrease social interaction. In the high-light version of the then test, the arena is brightly illuminated and this creates an aversive situation for the animals, which results in low levels of social interaction. In this configuration, it is possible to identify drugs or manipulations that reduce the inferred level of anxiety in the animals, that is, they result in an increased level of social interaction. In the low-light version, the arena is only illuminated with low, typically red light in order to minimize aversive cues. In this configuration, the level of interaction will be maximal and it is possible to test drugs or manipulations that reduce the normal level of social interactions. In addition to light level, which is the strongest experimental factor, the animals’ familiarity with the arena can be varied, for example, by having been introduced to the arena prior to the testing session, and whether the animals know each other prior to the testing session. Familiarity with the arena will reduce the level of aversive cues, but will also increase the level of territorial behavior, resulting in more fighting between the animals. Familiarity between the animals being tested can reduce the level of aversive cues during the testing situation and the level of fighting, because a hierarchy does not have to be established, but it may also increase variability in the data, because the animals will have a preestablished rank that not will be present if they are unfamiliar to each other. © 2010 Springer-Verlag Berlin Heidelberg