ABSTRACT
Psychoactive substances act on the central nervous system producing changes in mental processes, such as perception, consciousness, cognition or mood and emotions. The present study aims to identify: (i) the most used psychoactive substances, (ii) how psychoactive substances are acquired, (iii) and possible reasons for the use of psychoactive substances amongst university students. A literature search was carried out without language restrictions and included articles published between 2019 and 2020 in journals indexed in the electronic databases of Pubmed and Scielo. The inclusion criteria considered were: (i) original articles, (ii) studies carried out with university students, (iii) providing data on the use of psychoactive substances. 15 studies were included in this review, of which: 4 studies addressed possible reasons that lead to use of psychoactive substances, 10 studies reported usage profile and demographic data, and 1 study addressed how students acquire psychoactive substances. Reasons that led to the consumption of psychoactive substances include: feelings of loneliness after moving away from family; difficulty making new friends; poor academic performance and susceptible environment to acquisition of these substances. In the selected studies, alcohol was identified as the main drug used. In light of the findings reported in this review, new prevention and harm reduction measures can be formulated, based mainly on the reasons that lead to the use of psychoactive drugs, consumption patterns and how the drugs were acquired by university students.
ABSTRACT
BACKGROUND: Stroke is a leading cause of death and disability worldwide. A major factor in brain damage following ischemia is excitotoxicity caused by elevated levels of the neurotransmitter glutamate. In the brain, glutamate homeostasis is a primary function of astrocytes. Amburana cearensis has long been used in folk medicine and seed extract obtained with dichloromethane (EDAC) have previously been shown to exhibit cytoprotective activity in vitro. The aim of the present study was to analyse the activity of EDAC in hippocampal brain slices. METHODS: We prepared a dichloromethane extract (EDAC) from A. cearensis seeds and characterized the chemical constituents by 1H and 13C-NMR. Hippocampal slices from P6-8 or P90 Wistar rats were used for cell viability assay or glutamate uptake test. Hippocampal slices from P10-12 transgenic mice SOX10-EGFP and GFAP-EGFP and immunofluorescence for GS, GLAST and GLT1 were used to study oligodendrocytes and astrocytes. RESULTS: Astrocytes play a critical role in glutamate homeostasis and we provide immunohistochemical evidence that in excitotoxicity EDAC increased expression of glutamate transporters and glutamine synthetase, which is essential for detoxifying glutamate. Next, we directly examined astrocytes using transgenic mice in which glial fibrillary acidic protein (GFAP) drives expression of enhanced green fluorescence protein (EGFP) and show that glutamate excitotoxicity caused a decrease in GFAP-EGFP and that EDAC protected against this loss. This was examined further in the oxygen-glucose deprivation (OGD) model of ischemia, where EDAC caused an increase in astrocytic process branching, resulting in an increase in GFAP-EGFP. Using SOX10-EGFP reporter mice, we show that the acute response of oligodendrocytes to OGD in hippocampal slices is a marked loss of their processes and EDAC protected oligodendrocytes against this damage. CONCLUSION: This study provides evidence that EDAC is cytoprotective against ischemia and glutamate excitotoxicity by modulating astrocyte responses and stimulating their glutamate homeostatic mechanisms.
