1,721,006 research outputs found
Editorial of special issue – Synthetic psychoactive substances and neurological diseases: Toxic and therapeutic effects
No full textDiabetes, a contemporary risk for Parkinson’s disease: Epidemiological and cellular evidences
No full textDiabetes mellitus (DM), a group of diseases characterized by defective glucose metabolism, is the most widespread metabolic disorder affecting over 400 million adults worldwide. This pathological condition has been implicated in the pathogenesis of a number of central encephalopathies and peripheral neuropathies. In further support of this notion, recent epidemiological evidence suggests a link between DM and Parkinson’s disease (PD), with hyperglycemia emerging as one of the culprits in neurodegeneration involving the nigrostriatal pathway, the neuroanatomical substrate of the motor symptoms affecting parkinsonian patients. Indeed, dopaminergic neurons located in the mesencephalic substantia nigra appear to be particularly vulnerable to oxidative stress and degeneration, likely because of their intrinsic susceptibility to mitochondrial dysfunction, which may represent a direct consequence of hyperglycemia and hyperglycemia-induced oxidative stress. Other pathological pathways induced by increased intracellular glucose levels, including the polyol and the hexosamine pathway as well as the formation of advanced glycation end-products, may all play a pivotal role in mediating the detrimental effects of hyperglycemia on nigral dopaminergic neurons. In this review article, we will examine the epidemiological as well as the molecular and cellular clues supporting the potential susceptibility of nigrostriatal dopaminergic neurons to hyperglycemia
Dopamine and adenosine receptor interaction as the basis for the treatment of Parkinson's disease
No full textStudies in animal models of Parkinson’s disease (PD) and preliminary clinical trials have
shown that adenosine A2A antagonists might be useful in the treatment of the disease. In
order to study the effect of A2A blockade on parkinsonian tremor and on long-term
modifications produced by chronic L-DOPA, we have evaluated: (i) the effect of the A2A
antagonist SCH 58261 on jaw tremor induced by tacrine; (ii) GAD 67 mRNA in basal
ganglia, by in situ hybridization in 6-hydroxydopamine (6-OHDA) lesioned rats chronically
treated with SCH 58261 + L-DOPA or L-DOPA alone, as model of dyskinesia. (i)
Intact rats receiving tacrine (2.5 mg/kg) display bursts of jaw movements, which were
counteracted by parenteral administration of SCH 58261 (5 mg/kg). (ii) Acute administration
of SCH 58261 + L-DOPA, potentiates the rotational behaviour induced by LDOPA
indicating anti PD activity of A2A antagonists. Chronic administration of SCH
58261 (5 mg/kg) plus L-DOPA (3 mg/kg) or L-DOPA (6 mg/kg) alone, at doses producing
the same intensity of rotational behaviour during the first administration, showed not
changes and an increase in GAD67 mRNA in the GP respectively. Moreover, in the SNr, a
significant decrease in GAD67 mRNA was observed after both treatments. However, while
L-DOPA (6 mg/kg) decreased GAD67 mRNA below the intact side, SCH 58261 plus
L-DOPA (3 mg/kg) brought the GAD67 mRNA level increased by the lesion, to the same
level of the intact SNr. Antagonism of A2A receptors effectively counteracts the motor
impairment and tremor, which characterize PD. Moreover, long-term L-DOPA administration
produces changes in basal ganglia activity which appear to be responsible of
dyskinetic effects, whereas chronic administration of A2A antagonists + L-DOPA produces
little or no changes in basal ganglia suggesting that this treatment has low dyskinetic
potential
Selective adenosine A2A receptor antagonists suppress jaw movements in the rat tacrine model of parkinsonian tremor
No full textBlockade of pallidal adenosine A2A receptors potentiates contralateral rotational behavior induced by L-DOPA and dopaminergic agonists in hemiparkinsonian rats
No full textAssociation between Novel Object Recognition/Spontaneous Alternation Behavior and Emission of Ultrasonic Vocalizations in Rats: Possible Relevance to the Study of Memory
Full text linkRats emit ultrasonic vocalizations (USVs) in situations with emotional valence, and USVs have also been proposed as a marker for memories conditioned to those situations. This study investigated whether USV emissions can predict and/or be associated with the behavior of rats in tests that evaluate unconditioned memory. To this end, rats were subjected to “tickling”, a procedure of heterospecific play that has emotional valence and elicits the emission of USVs, and afterwards evaluated in the novel object recognition test (NOR) and in the single trial continuous spontaneous alternation behavior (SAB) test in a Y maze. The number of 22-kHz USVs (aversive) and 50-kHz USVs (appetitive) emitted in response to tickling and during NOR and SAB tests were scored, and the correlations among them and with rats’ behavior evaluated. Rats emitted 50-kHz USVs, but not 22-kHz USVs, during the NOR and SAB tests, and such calling behavior was not linked with the behavioral readouts indicative of memory function in either test. However, rats that prevalently emitted 22-kHz USVs in response to tickling displayed an impaired NOR performance. These findings suggest that measuring the emission of USVs could be of interest in studies of unconditioned memory, at least with regard to 22-kHz USVs
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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