RESUMEN
Crack cocaine is a highly toxic drug with great potential to induce addiction. It produces more intense effects than cocaine powder, with its use having grown worldwide. However, few studies have focused on the cognitive and biochemical consequences that result from crack cocaine inhalation. This study examined the effects of direct crack cocaine inhalation on spatial working memory and brain oxidative stress parameters in rats. Male adult Wistar rats, well-trained in an eight-arm radial maze (8-RM), underwent five sessions of crack cocaine inhalation (crack cocaine group) once a day or inhalation simulation (sham group), being tested in 1-h delayed tasks 24â¯h after the last inhalation. An additional inhalation session was carried out the following day, with the prefrontal cortex, hippocampus and striatum being removed five minutes afterwards in order to assess oxidative damage such as lipid peroxidation, thiobarbituric acid-reactive species (TBARS) levels, and advanced oxidation protein products (AOPP), as well as the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Animals from the crack cocaine group showed more errors (pâ¯<⯠0.01) in the 1-h post-delay performance in the 8-RM when compared to the sham group. The crack cocaine group showed decreased (pâ¯<⯠0.05) lipid peroxidation in the hippocampus and increased (pâ¯<⯠0.001) levels of AOPP and SOD activity (pâ¯<â¯0.05) in the striatum when compared to the sham group. Therefore, the repeated inhalation of crack cocaine impaired long-term spatial working memory and elicited oxidative stress in the hippocampus and striatum of rats.
Asunto(s)
Cocaína Crack/administración & dosificación , Trastornos de la Memoria/inducido químicamente , Estrés Oxidativo/efectos de los fármacos , Administración por Inhalación , Productos Avanzados de Oxidación de Proteínas/metabolismo , Animales , Catalasa/metabolismo , Modelos Animales de Enfermedad , Cromatografía de Gases y Espectrometría de Masas , Glutatión Peroxidasa/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Memoria a Corto Plazo/efectos de los fármacos , Ratas , Ratas Wistar , Superóxido Dismutasa/metabolismoRESUMEN
When burning crack cocaine, the pyrolysis of cocaine generates anhydroecgonine methyl ester (AEME). AEME has been shown to be highly neurotoxic but its effects on cognitive function and oxidative stress are still unknown. Thus, this study investigated the effects of AEME on spatial working memory and on parameters of oxidative stress in the prefrontal cortex, hippocampus, and striatum. First, 18 well-trained rats in 8-arm radial maze (8-RM) procedures received acute intracerebroventricular (icv) administration of AEME at doses of 10, 32, or 100 µg or saline (SAL) in a counterbalanced order and were tested 5 min later in 1-h delayed tasks in the 8-RM. Secondly, separated animals received acute icv administration of AEME at doses of 10 (n = 5), 32 (n = 5), or 100 µg (n = 5) or SAL (n = 5) for analysis of advanced oxidation protein products, thiobarbituric acid, catalase, glutathione peroxidase, and superoxide dismutase. A higher number of errors were seen in the 1-h post-delay performance after AEME 32 µg and AEME 100 µg when compared to SAL. In the striatum, animals receiving AEME 100 µg icv showed increased advanced oxidation protein products levels when compared to 10 µg, and also showed increased activity of glutathione peroxidase enzyme when compared to SAL but also comparing to AEME 32 µg and AEME 10 µg. These results showed that AEME impairs long-term spatial working memory and also induces greater protein oxidation and increased levels of antioxidant enzymes in the striatum.