Clinical studies show that physical exercise has anxiolytic and pro-cognitive properties for both healthy individuals and psychiatric patients. Most of these data refer to the effects of aerobic exercise. However, other modalities such as resistance exercise deserve more attention because they may also modulate brain function. This study aimed to compare the effects of an aerobic exercise protocol on a treadmill and a resistance exercise protocol on a ladder apparatus on anxiety-like behavior, cognitive flexibility, and neuroplasticity parameters in healthy animals. Adult male Wistar rats were divided into three groups: sedentary control, aerobic training, and resistance training. Subsequently, they were evaluated in the elevated plus-maze (EPM), light-dark box, and modified hole board (mHB) tests. The expressions of synaptophysin and postsynaptic plasticity protein 95 in the dorsal and ventral hippocampus were analyzed by immunofluorescence. The results demonstrated an anxiolytic effect promoted by exercise in the EPM, particularly in the animals submitted to aerobic training, and a mild pro-learning effect of both exercise modalities was observed in the mHB test. All groups showed similar outcomes in the other evaluations. Therefore, the exercise modalities investigated in the present study did not provide considerable modifications to such aspects of the emotional/cognitive functions and neuroplasticity under physiological contexts. Perhaps the two types of exercise acted in neurobiological pathways not analyzed in this study, or the effects may emerge under pathological contexts. These hypotheses should be tested in future studies.
1 May 2017 in International Journal of Developmental Neuroscience
Methylphenidate (MPH) is a stimulant drug mainly prescribed to treat cognitive impairments in attention-deficit/hyperactivity disorder (ADHD). We demonstrated that neonatal hypoxia-ischemia (HI) induced attentional deficits in rats and MPH administration reversed these deficits. However, MPH effects on memory deficits after the HI procedure have not been evaluated yet. We aimed to analyze learning and memory performance of young hypoxic-ischemic rats after MPH administration and associate their performance with brain-derived neurotrophic factor (BDNF) levels in the prefrontal cortex and hippocampus. Male Wistar rats were divided into four groups (n=11–13/group): control saline (CTS), control MPH (CTMPH), HI saline (HIS) and HIMPH. The HI procedure was conducted at post-natal day (PND) 7 and memory tasks between PND 30 and 45. MPH administration (2.5 mg/kg, i.p.) occurred 30 min prior to each behavioral session and daily, for 15 days, for the BDNF assay (n=5–7/group). As expected, hypoxic-ischemic animals demonstrated learning and memory deficits in the novel-object recognition (NOR) and Morris water maze (MWM) tasks. However, MPH treatment did not improve learning and memory deficits of these animals in the MWM—and even disrupted the animals’ performance in the NOR task. Increased BDNF levels were found in the hippocampus of HIMPH animals, which seem to have been insufficient to improve memory deficits observed in this group. The MPH treatment was not able to improve memory deficits resulting from the HI procedure considering a dose of 2.5 mg/kg. Further studies investigating different MPH doses would be necessary to determine a dose–response relationship in this model.