Impairment of spatial working memory and oxidative stress induced by repeated crack cocaine inhalation in rats.

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 24 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 (p <  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 (p <  0.05) lipid peroxidation in the hippocampus and increased (p <  0.001) levels of AOPP and SOD activity (p < 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.

Auditory Processing Assessment in Children with Attention Deficit Hyperactivity Disorder: An Open Study Examining Methylphenidate Effects

Abstract Introduction Children with Attention Deficit Hyperactivity Disorder can present Auditory Processing (AP) Disorder. Objective The study examined the AP in ADHD children compared with non-ADHD children, and before and after 3 and 6 months of methylphenidate (MPH) treatment in ADHD children. Methods Drug-naive children diagnosed with ADHD combined subtype aging between 7 and 11 years, coming from public and private outpatient service or public and private school, and age-gender-matched non-ADHD children, participated in an open, non-randomized study from February 2013 to December 2013. They were submitted to a behavioral battery of AP tests comprising Speech with white Noise, Dichotic Digits (DD), and Pitch Pattern Sequence (PPS) and were compared with non-ADHD children. They were followed for 3 and 6 months of MPH treatment (0.5 mg/kg/day). Results ADHD children presented larger number of errors in DD (p < 0.01), and less correct responses in the PPS (p < 0.0001) and in the SN (p < 0.05) tests when compared with non-ADHD children. The treatment with MPH, especially along 6 months, significantly decreased the mean errors in the DD (p < 0.01) and increased the correct response in the PPS (p < 0.001) and SN (p < 0.01) tests when compared with the performance before MPH treatment. Conclusions ADHD children show inefficient AP in selected behavioral auditory battery suggesting impaired in auditory closure, binaural integration, and temporal ordering. Treatment with MPH gradually improved these deficiencies and completely reversed them by reaching a performance similar to non-ADHD children at 6 months of treatment.

Auditory Processing Assessment in Children with Attention Deficit Hyperactivity Disorder: An Open Study Examining Methylphenidate Effects.

Introduction Children with Attention Deficit Hyperactivity Disorder can present Auditory Processing (AP) Disorder. Objective The study examined the AP in ADHD children compared with non-ADHD children, and before and after 3 and 6 months of methylphenidate (MPH) treatment in ADHD children. Methods Drug-naive children diagnosed with ADHD combined subtype aging between 7 and 11 years, coming from public and private outpatient service or public and private school, and age-gender-matched non-ADHD children, participated in an open, non-randomized study from February 2013 to December 2013. They were submitted to a behavioral battery of AP tests comprising Speech with white Noise, Dichotic Digits (DD), and Pitch Pattern Sequence (PPS) and were compared with non-ADHD children. They were followed for 3 and 6 months of MPH treatment (0.5 mg/kg/day). Results ADHD children presented larger number of errors in DD (p < 0.01), and less correct responses in the PPS (p < 0.0001) and in the SN (p < 0.05) tests when compared with non-ADHD children. The treatment with MPH, especially along 6 months, significantly decreased the mean errors in the DD (p < 0.01) and increased the correct response in the PPS (p < 0.001) and SN (p < 0.01) tests when compared with the performance before MPH treatment. Conclusions ADHD children show inefficient AP in selected behavioral auditory battery suggesting impaired in auditory closure, binaural integration, and temporal ordering. Treatment with MPH gradually improved these deficiencies and completely reversed them by reaching a performance similar to non-ADHD children at 6 months of treatment.