Elucidating the neuropharmacological properties of the novel psychoactive substance and synthetic cathinone, mephedrone

Mephedrone (4-methylmethcathinone) is an illicit psychoactive stimulant and synthetic cathinone which gained prominence in the UK as a “legal high” circa 2008, subsequently being made illegal following media reports of adverse effects and links to several fatalities, as well as its structural similarity to amphetamine. Today, mephedrone remains in recreational use worldwide, often consumed alongside traditional illicit substances such as methamphetamine and gamma-hydroxybutyrate (GHB), or legal drugs such as caffeine and alcohol. In rats, co-administration of caffeine with MDMA (3,4-methylenedioxymephampethamine), has been shown to potentiate the elevation of extracellular 5-HT brain levels, a neurochemical correlate of the serotonin syndrome. In humans, this syndrome is characterised by adverse physiological effects including fever, agitation and hypertension. Despite increased elucidation of its pharmacological profile since 2008, there remains a paucity of data on mephedrone’s behavioural and neurochemical effects, particularly when combined with caffeine. The present thesis sought to somewhat mitigate this deficit. First, a repeated dosing regimen was designed to assess the acute effects of repeated mephedrone administration, with and without caffeine, on behavioural and physiological measures in adolescent rats, and any lasting changes in anxiety, cognition and microglial activation in adulthood. Second, following the observation of hyperthermia and stereotyped behaviours in adolescent rats, an in vivo microdialysis study was designed to elucidate whether this apparent serotonin syndrome was elicited via increased downstream activation of postsynaptic 5-HT1A receptors by endogenous 5-HT. In sum, mephedrone elicited changes in body temperature and locomotor hyperactivity in both studies (with tolerance to the latter developing throughout the one-week binge-type dosing period in study 1). In each case, caffeine converted mephedrone-induced hypothermia to hyperthermia, and enhanced mephedrone-induced stereotyped behaviours. Pre-administration of the 5-HT1A receptor antagonist WAY-100,635 failed to prevent any of these effects, and in fact sped the onset of the hyperthermic response, perhaps via downstream effects following binding to 5-HT1A autoreceptors in the dorsal raphe nuclei. Nonetheless, no lasting effects of mephedrone, caffeine, or the combination of each, were observed on recognition memory, anxiety, sensorimotor gating, conditioned freezing or hippocampal microglial activation

Activation of the pro-resolving receptor Fpr2 attenuates inflammatory microglial activation

Poster number: P-T099 Theme: Neurodegenerative disorders & ageing Activation of the pro-resolving receptor Fpr2 reverses inflammatory microglial activation Authors: Edward S Wickstead - Life Science & Technology University of Westminster/Queen Mary University of London Inflammation is a major contributor to many neurodegenerative disease (Heneka et al. 2015). Microglia, as the resident immune cells of the brain and spinal cord, provide the first line of immunological defence, but can become deleterious when chronically activated, triggering extensive neuronal damage (Cunningham, 2013). Dampening or even reversing this activation may provide neuronal protection against chronic inflammatory damage. The aim of this study was to determine whether lipopolysaccharide (LPS)-induced inflammation could be abrogated through activation of the receptor Fpr2, known to play an important role in peripheral inflammatory resolution. Immortalised murine microglia (BV2 cell line) were stimulated with LPS (50ng/ml) for 1 hour prior to the treatment with one of two Fpr2 ligands, either Cpd43 or Quin-C1 (both 100nM), and production of nitric oxide (NO), tumour necrosis factor alpha (TNFα) and interleukin-10 (IL-10) were monitored after 24h and 48h. Treatment with either Fpr2 ligand significantly suppressed LPS-induced production of NO or TNFα after both 24h and 48h exposure, moreover Fpr2 ligand treatment significantly enhanced production of IL-10 48h post-LPS treatment. As we have previously shown Fpr2 to be coupled to a number of intracellular signaling pathways (Cooray et al. 2013), we investigated potential signaling responses. Western blot analysis revealed no activation of ERK1/2, but identified a rapid and potent activation of p38 MAP kinase in BV2 microglia following stimulation with Fpr2 ligands. Together, these data indicate the possibility of exploiting immunomodulatory strategies for the treatment of neurological diseases, and highlight in particular the important potential of resolution mechanisms as novel therapeutic targets in neuroinflammation. References Cooray SN et al. (2013). Proc Natl Acad Sci U S A 110: 18232-7. Cunningham C (2013). Glia 61: 71-90. Heneka MT et al. (2015). Lancet Neurol 14: 388-40

Improving somatic health for outpatients with severe mental illness: the development of an intervention

Objective: Patients with severe mental illness (SMI) suffer from more somatic illness than the general population. Possible causes are side effects of neuropsychiatric medication, genetic vulnerability, insufficient health care and lifestyle. This co-morbidity is potentially reversible and augments the costs for health care and diminishes quality of life. Screening on symptoms and risks of somatic diseases and coordination of care are proposed to improve SMI-patients' somatic health status. Methods: A clinical facility was started to improve the somatic health status of patients in an outpatient centre in southern Netherlands. This outpatient centre was added to the specialized care for severe and enduring SMI. The intervention consisted of the inventarisation of side-effects and the detection of gaps in health care provision for 72 patients. This was based on interviewing the patients, laboratory screening, collecting information from their general practitioner and pharmacy. A list was compiled of possible diagnosis and health risks, and a plan of action was made for the treatment. Healthcare consumption, quality of life and general functioning were assessed to analyze cost-effectiveness. Evaluations were performed with the psychiatric care team on the process. Results: Mean annual cost of GP's and medical specialist's consultations were E492. There existed a negative relation between EQ5D VAS and the number of self reported chronic diseases. Conclusion: The authors conclude that the procedure is well feasible, but should be set up in close collaboration with all health care professionals of these patients to make tailor made solutions possible

Investigating working memory impairments in individuals with autism spectrum disorder

Autism spectrum disorders (ASD) are lifelong neurodevelopmental disorders characterized by communication difficulties, social impairment and fixated interests along with repetitive behaviours. Although neuropsychological impairments are not part of diagnostic criteria, many people with ASD experience significant cognitive impairments. Executive function deficits are commonly experienced by individuals with ASD, and WM which plays an important role in human cognition and a central role in executive function has been reported to be impaired in individuals with ASD. Studies examining whether individuals with ASD experience significant WM impairments have produced inconsistent findings thus it is not clear whether WM deficits are commonly experienced by individuals with ASD. Therefore, Chapter 2 investigated whether individuals with ASD experience significant impairments in WM and whether there are specific domains of working memory that are impaired while controlling for age and IQ as potential moderators. The findings of this chapter indicate that across the lifespan, individuals with ASD demonstrate large impairments in WM across both phonological and visuospatial WM domains when compared to healthy individuals. The importance and role of working memory to everyday tasks is well established, but research has yet to investigate if the WM deficiencies reported on cognitive tasks are translated to difficulties with everyday life. To investigate this question, Chapter 4 explored whether individuals with ASD experience significant everyday WM related difficulties and if they are everyday concern of adults with ASD. 111 males with ASD between the ages of 18 and 35 who were recruited through the National Health Service Greater Glasgow and Clyde, completed the WMQ, a self-assessment questionnaire. This finding reveals that individuals with high functioning autism display significant impairment in WM related difficulties in everyday life. It is evident from Chapter 3 and 4, that WM deficiencies is a definite problem in individuals with ASD. With WM impairments being present in multiple psychiatric disorders, there has been urgent need for effective treatment options. While both pharmacological and non-pharmacological approaches have shown positive results, both are far from leading to a significant improvement in WM in patients with ASD. In the last 15 years, there has been a growing interest in the use of non-invasive brain stimulation methods such as transcranial direct current stimulation (tDCS) as a way of improving WM in typically developed individuals and in clinical populations. In chapter 5 a phase II trial was conducted to evaluate the adverse effects of tDCS and investigate whether anodal tDCS lead to an improvement in working memory accuracy scores when administered over the left DLPFC when compared to sham in adults with high functioning autism. Additionally, we investigated whether the observed effect of tDCS over the left DLPFC and working memory scores is dependent on polarity anodal (positive) versus cathodal (negative) stimulation). A random sample of 50 male participants consisting of 25 individuals with HFA and 25 typical developed (TD), between the ages of 18-35 with a mean age of 24.33 (SD=3.80) took part in this study. All self-reported that they had normal or corrected vision, normal colour vision and passed the tDCS safety screening process. Participants underwent three experimental conditions: anodal, cathodal and sham stimulation. One session involved anodal stimulation over the DLPFC (F3) with the cathode placed over the contralateral supraorbital area. The next session involved the same protocol but the cathode electrode was placed over the DLPFC and the anode over the contralateral supraorbital area. The third and final session involved sham stimulation where the current was ‘ramped-up’ for 30 seconds and then ramped down to 0 milliamps over 30 seconds. Participants performed the 3-back working memory task pre, during and post stimulation; tDCS was then applied at a current of 1.5 milliamps for 15 minutes. The findings of this study demonstrated that anodal tDCS for 15 minutes at an intensity of 1.5 mA led to an improvement in WM performance scores when administered over the left DLPFC when compared to baseline, cathodal and sham stimulation of the same area in adults with HFA. The results of this thesis provide evidence of significantly impaired WM in the literature and everyday life in individuals with ASD. Moreover, it also provides evidence for the possible therapeutic application of tDCS for WM impairments