The labels and models used to describe problematic substance use impact discrete elements of stigma: A Registered Report

Objectives: Problematic substance use is one of the most stigmatised health conditions leading research to examine how the labels and models used to describe it influence public stigma. Two recent studies examine whether beliefs in a disease model of addiction influence public stigma but result in equivocal findings – in line with the mixed-blessings model, Kelly et al. (2021) found that whilst the label ‘chronically relapsing brain disease’ reduced blame attribution, it decreased prognostic optimism and increased perceived danger and need for continued care; however, Rundle et al. (2021) conclude absence of evidence. This study isolates the different factors used in these two studies to assess whether health condition (drug use vs. health concern), aetiological label (brain disease vs. problem), and attributional judgement (low vs. high treatment stability) influence public stigma towards problematic substance use. Methods: 1613 participants were assigned randomly to one of eight vignette conditions that manipulated these factors. They completed self-report measures of discrete and general public stigma and an indirect measure of discrimination. Results: Greater social distance, danger, and public stigma but lower blame were ascribed to drug use relative to a health concern. Greater (genetic) blame was reported when drug use was labelled as a ‘chronically relapsing brain disease’ relative to a ‘problem’. Findings for attributional judgement were either inconclusive or statistically equivalent. Discussion: The labels used to describe problematic substance use appear to impact discrete elements of stigma. We suggest that addiction is a functional attribution, which may explain the mixed literature on the impact of aetiological labels on stigma to date

The labels and models used to describe problematic substance use impact discrete elements of stigma: A registered report.

Objectives: Problematic substance use is one of the most stigmatized health conditions leading research to examine how the labels and models used to describe it influence public stigma. Two recent studies examine whether beliefs in a disease model of addiction influence public stigma but result in equivocal findings — in line with the mixed-blessings model, Kelly et al. (2021) found that while the label “chronically relapsing brain disease” reduced blame attribution, it decreased prognostic optimism and increased perceived danger and need for continued care; however,Rundle et al. (2021) conclude absence of evidence. This study isolates the different factors used in these two studies to assess whether health condition (drug use vs. health concern), etiological label (brain disease vs. problem), and attributional judgment (low vs. high treatment stability) influence public stigma toward problematic substance use. Method: Overall, 1,613 participants were assigned randomly to one of the eight vignette conditions that manipulated these factors. They completed self-report measures of discrete and general public stigma and an indirect measure of discrimination. Results: Greater social distance, danger, and public stigma but lower blame were ascribed to drug use relative to a health concern. Greater (genetic) blame was reported when drug use was labeled as a“chronically relapsing brain disease” relative to a “problem”. Findings for attributional judgment were either inconclusive or statistically equivalent. Discussion: The labels used to describe problematic substance use appear to impact discrete elements of stigma. We suggest that addiction is a functional attribution, which may explain the mixed literature on the impact of etiological labels on stigma to date

Rabies virus glycoprotein enhances spatial memory via the PDZ binding motif

“This is a pre-print of an article published in J. Neurovirol. The final authenticated version is available online at: https://doi.org/10.1007/s13365-021-00972-2”International audienceRabies is a life-threatening viral infection of the brain. Rabies virus (RABV) merely infects excitable cells including neurons provoking drastic behaviors including negative emotional memories. RABV glycoprotein (RVG) plays a critical role in RABV pathogenesis. RVG interacts with various cytoplasmic PDZ (PSD-95/Dlg/ZO-1) containing proteins through its PDZ binding motif (PBM). PTZ domains have crucial role in formation and function of signal transduction. Hippocampus is one of the cerebral regions that contains high load of viral antigens. We examined impact of RVG expression in the dorsal hippocampus on aversive as well as spatial learning and memory performance in rats. Two μl of the lentiviral vector (~108 T.U. /ml) encoding RVG or ∆RVG (deleted PBM) genomes was microinjected into the hippocampal CA1. After one week, rat’s brain was cross-sectioned and RVG/∆RVG-expressing neuronal cells were confirmed by fluorescent microscopy. Passive avoidance and spatial learning and memory were assessed in rats by Shuttle box and Morris water maze (MWM). In the shuttle box, both RVG and ∆RVG decreased the time spent in the dark compartment compared to control (p<0.05). In MWM, RVG and ∆RVG did not affect the acquisition of spatial task. RVG-expressing rats reached the platform position in the probe test sooner than control and ∆RVG groups (p<0.05). Rats expressing ∆RVG significantly swam farther from the hidden platform than RVG group (p<0.05). Our data indicate RVG expression in the hippocampus strengthens aversive and spatial learning and memory performance. The boosting effect on spatial but not avoidance memory is mediated through PBM

Lentiviral Expression of Rabies Virus Glycoprotein in the Rat Hippocampus Strengthens Synaptic Plasticity

“This is a pre-print of an article published in journal of Cellular and Molecular Neurobiology. The final authenticated version is available online at: https://doi.org/10.1007/s10571-020-01032-9"International audienceRabies virus (RABV) is a neurotropic virus exclusively infecting neurons in the central nervous system. RABV encodes five proteins. Among them, the viral glycoprotein (RVG) plays a key role in viral entry into neurons and rabies pathogenesis. It was shown that the nature of the C-terminus of the RABV G protein, which possesses a PDZ-binding motif (PBM), modulates the virulence of the RABV strain. The neuronal protein partners recruited by this PBM may alter host cell function. This study was conducted to investigate the effect of RVG on synaptic function in the hippocampal dentate gyrus (DG) of rat. Two μl (108 T.U./ml) of the lentiviral vector containing RVG gene was injected into the DG of rat hippocampus. After 2 weeks, the rat’s brain was cross-sectioned and RVG-expressing cells were detected by fluorescent microscopy. Hippocampal synaptic activity of the infected rats was then examined by recording the local field potentials from DG after stimulation of the perforant pathway. Short-term synaptic plasticity was also assessed by double pulse stimulation. Expression of RVG in DG increased long-term potentiation population spikes (LTP-PS), whereas no facilitation of LTP-PS was found in neurons expressing δRVG (deleted PBM). Furthermore, RVG and δRVG strengthened paired-pulse facilitation. Heterosynaptic long-term depression (LTD) in the DG was significantly blocked in RVG-expressing group compared to the control group. This blockade was dependent to PBM motif as rats expressing δRVG in the DG-expressed LTD comparable to the RVG group. Our data demonstrate that RVG expression facilitates both short- and long-term synaptic plasticity in the DG indicating that it may involve both pre- and postsynaptic mechanisms to alter synaptic function. Further studies are needed to elucidate the underlying mechanisms