Emotional, cognitive and neurochemical alterations in a premotor stage model of Parkinson's disease
Authors: C P Figueiredo
E Cargnin-Ferreira
R N Takahashi
M T Tadaiesky
P A Dombrowski
C Da Cunha
Journal: Neuroscience (2008)
Discipline: NEUROSCIENCE & BEHAVIOR
Keywords: Parkinson's disease; cognitive deficits; emotional deficits; dopaminergic neurons; 6-hydroxydopamine
Affiliations: Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, UFSC, Campus Universitário, Trindade, Florianópolis, SC, Brazil.

Abstract:  In addition to classic motor symptoms, Parkinson's disease (PD) is characterized by cognitive and emotional deficits, which have been demonstrated to precede motor impairments. The present study addresses the question of whether a partial degeneration of dopaminergic neurons using 6-hydroxydopamine (6-OHDA) in rats is able to induce premotor behavioral signs. The time-course of nigrostriatal damage was evaluated by tyrosine hydroxylase immunohistochemistry and the levels of dopamine, noradrenaline, and 5-HT in various brain regions were analyzed by high performance liquid chromatography (HPLC). Behavioral tests that assessed a variety of psychological functions, including locomotor activity, emotional reactivity and depression, anxiety and memory were conducted on 6-OHDA lesioned rats. Bilateral infusion of 6-OHDA in the striatum of rats caused early (1 week) damage of dopaminergic terminals in striatum and in cell bodies in substantia nigra pars compacta. The nigrostriatal lesion was accompanied by early loss of dopamine in the striatum, which remained stable through a 3-week period of observation. In addition, a late (3 weeks) loss of dopamine in the prefrontal cortex, but not in the hippocampus, was seen. Additional noradrenergic and serotonergic alterations were observed after 6-OHDA administration. The results indicated that 6-OHDA lesioned rats show decreased sucrose consumption and an increased immobility time in the forced swimming test, an anhedonic-depressive-like effect. In addition, an anxiogenic-like activity in the elevated plus maze test and cognitive impairments were observed on the cued version of the Morris water maze and social recognition tests. These findings suggest that partial striatal dopaminergic degeneration and parallel dopaminergic, noradrenergic and serotonergic alterations in striatum and prefrontal cortex may have caused the emotional and cognitive deficits observed in this rat model of early phase PD. 

Retracted: No

PubPeer comments:
 This paper belongs to a set of over 400 papers (as per February 2020) that share very similar Western blots with tadpole-like shaped bands, the same background pattern, and striking similarities in title structures, paper layout, bar graph design, and - in a subset - flow cytometry panels. Despite these similarities, these papers are authored by researchers from different departments and institutes, with almost no overlap in authors. The list of these papers is available here: https: docs.google.com spreadsheets d 1KXqTAyl4j-jVorFPMD2XRpr76LcIKJ0CVyIvRj0exYQ edit?usp=sharing A more detailed description of this set of papers, suspected to all be generated by a common source, a paper mill , can be found here: * https: forbetterscience.com 2020 01 24 the-full-service-paper-mill-and-its-chinese-customers (January 2020) * https: scienceintegritydigest.com 2020 02 21 the-tadpole-paper-mill (February 2020) The same paper mill has been described in these papers: * Jana Christopher - Systematic fabrication of scientific images revealed - FEBS Letters (2018) - https: febs.onlinelibrary.wiley.com doi full 10.1002 1873-3468.13201 * Jennifer A Byrne and Jana Christopher - Digital magic, or the dark arts of the 21st centuryu2014how can journals and peer reviewers detect manuscripts and publications from paper mills? - FEBS Letters (2020) - https: febs.onlinelibrary.wiley.com doi full 10.1002 1873-3468.13747 , 
 Retracted [December 2020] .  This article has been retracted at the request of the Editor-in-Chief as there are concerns about the reliability of the results included in the article. The journal was initially contacted by the corresponding author to request the retraction as they reported that u201cthe study has some problems to be addressed and many sections need to be re-writtenu201d.  Given the comments of Dr. Elisabeth Bik https: scienceintegritydigest.com 2020 02 21 the-tadpole-paper-mill regarding this article, the journal requested the author to provide the raw data. However, the author was not able to fulfil this request. ,