Maternal voluntary physical exercise in the adult rat: evidence of exercise-associated differences in maternal food intake, and in brain effects on the progeny.

Objectives: Maternal physical activity may impact behavioral and electrophysiological aspects of brain function, with short- and long-term effects on pre- and postnatal neurodevelopment of the offspring. This study evaluated in the rat the effects of maternal voluntary physical activity (MVPA) on food intake and weight gain in the dams, as well as anxiety-like behavior, short-term memory and the brain excitability-related phenomenon known as cortical spreading depression (CSD) on the mother-pup dyad.Methods: Female Wistar rats (n=33) were individually housed in cages containing a running wheel for a 30-days adaptation period before mating. Rats were classified as inactive (I); active (A) or very active (VA) according to the distance spontaneously travelled daily. During gestation, the dams continued to have access to the running wheel. Mothers and their respective pups (1 pup per mother) were evaluated in the open field test (OFT), object recognition test (ORT), elevated plus maze test (EPMT) and the CSD propagation features.Results: MVPA was directly associated with increased food intake and weight gain during gestation, and maternal anxiolytic-like behavioral responses in the OFT. Pups from VA mothers showed a high discrimination index for shape recognition memory (ORT) and decreased propagation velocities of CSD, when compared with the inactive group.Discussion: The data suggest that MVPA during the gestational period induces neuroplasticity and may modulate the brain functions in the mother-infant dyad in the rat.

Treadmill Exercise Reverses the Adverse Effects of Intermittent Fasting on Behavior and Cortical Spreading Depression in Young Rats.

Intermittent fasting (IF) and physical exercise (PE) have beneficial psychological and physiological effects, improving memory and anxiety-like behavior. However, the impact of this combination on brain electrophysiological patterns is unknown. We aimed to evaluate the behavior and parameters of a brain excitability-related phenomenon named cortical spreading depression (CSD) in young rats (31-87 days of life) submitted to IF and treadmill PE for eight weeks. Sixty-four male and female Wistar rats aged 24 days were randomized into control, IF, PE, and IF+PE groups. Behavioral tests (open field (OF), object recognition, and elevated plus maze (EPM)) were performed, and the CSD propagation features were recorded. IF caused behavioral responses indicative of anxiety (lower number of entries and time spent in the OF center and EPM open arms). IF also reduced the discrimination index for object recognition memory tests and increased the propagation velocity of CSD. PE rats displayed more entries into the OF center and lowered CSD propagation speed. Data suggest that IF worsens anxiety-like behavior and memory and accelerates CSD in young rats. In contrast, PE reverted the unfavorable effects of IF. The brain effects of IF and PE at younger ages are recommended for study.

Effect of neonatal melatonin administration on behavioral and brain electrophysiological and redox imbalance in rats.

Introduction: Melatonin (MLT) reportedly has beneficial effects in neurological disorders involving brain excitability (e.g., Epilepsy and Migraine) and behavioral patterns (e.g., Anxiety and Depression). This study was performed to investigate, in the developing rat brain, the effect of early-in-life administration of two different doses of exogenous MLT on behavioral (anxiety and memory) and electrophysiological (CSD analysis) aspects of brain function. Additionally, brain levels of malondialdehyde (MDA) and superoxide dismutase (SOD), both cellular indicators of redox balance status, were evaluated. We hypothesize that MLT differentially affects the behavioral and CSD parameters as a function of the MLT dose. Materials and methods: Male Wistar rats received, from the 7th to the 27th postnatal day (PND), on alternate days, vehicle solution, or 10 mg/kg/or 40 mg/kg MLT (MLT-10 and MLT-40 groups), or no treatment (intact group). To perform behavioral and cognition analysis, from PND30 to PND32, they were tested in the open field apparatus, first for anxiety (PND30) and then for object recognition memory tasks: spatial position recognition (PND31) and shape recognition (PND32). On PND34, they were tested in the elevated plus maze. From PND36 to 42, the excitability-related phenomenon known as cortical spreading depression (CSD) was recorded, and its features were analyzed. Results: Treatment with MLT did not change the animals' body weight or blood glucose levels. The MLT-10 treatment, but not the MLT-40 treatment, was associated with behaviors that suggest less anxiety and improved memory. MLT-10 and MLT-40 treatments, respectively, decelerated and accelerated CSD propagation (speed of 2.86 ± 0.14 mm/min and 3.96 ± 0.16 mm/min), compared with the control groups (3.3 ± 0.10 mm/min and 3.25 ± 0.11 mm/min, for the intact and vehicle groups, respectively; p < 0.01). Cerebral cortex levels of malondialdehyde and superoxide dismutase were, respectively, lower and higher in the MLT-10 group but not in the MLT40 group. Conclusion: Our findings suggest that MLT intraperitoneal administration during brain development may differentially act as an antioxidant agent when administered at a low dose but not at a high dose, according to behavioral, electrophysiological, and biochemical parameters.

Protective effect of exogenous melatonin on testicular histopathology and histomorphometry of adult rats with domperidone-induced hyperprolactinemia.

Hyperprolactinemia is a pathological condition resulting from increased prolactin that directly affects reproduction, as this condition inhibits the release of LH, FSH and gonadal steroidogenesis, bringing several negative clinical associations in reproduction. In contrast, melatonin (MEL) plays an important role in the regulation of steroidogenesis and modulates damages to the process of spermatogenesis. The objective was to analyze the protective effects of exogenous melatonin on the testis of hyperprolactinemic adult rats. Forty-eight male rats were used, divided into two treatment periods: 30 and 60 days, each treatment was subdivided into three groups: Control, Hyper (hyperprolactinemia), and Hyper+MEL (hyperprolactinemia and melatonin). Treatment with melatonin was 200 µg/100 g, subcutaneously. Induction of hyperprolactinemia was obtained with a dose of 4 mg/kg of domperidone, subcutaneously. The results of the histopathology demonstrated that the animals in the Hyper group presented degeneration of germ cells when compared to the control. In addition, the degenerations were presented in smaller quantities in the Hyper+MEL, in both treatment periods, evidencing the benefits of the melatonin in gonadal regeneration. The Hyper group of both treatment periods showed a decrease in tubular diameter, epithelium height, and tubular area, in addition to a decrease in Sertoli cells, when compared to the control and the Hyper+MEL group. In conclusion, the hyperprolactinemia can affect the germinal epithelium and testicular microstructure; the exogenous melatonin has a protective effect against hyperprolactinemia, reducing testicular damage.