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Methylphenidate (MPH) is the active ingredient in Ritalin, although effective in treating ofthe attention deficit hyperactivity disorder (ADHD), its neurostimulation action is attractiveamong students in order to increase the focus or improving student performance. In context ofthe Developmental Origins of Health and Disease (DOHaD) concept, states that insults incritical phases of development, as the peripubertal period, may program the organism todysfunctions in adulthood. The aim of this work was to investigate the impact of peripubertalMPH exposure on learning and retrograde memory in adult rats. Male Wistar rats wereexposed to MPH (5 mg/kg) from post-natal day (PN) 30 until PN60 (MPH). Control animalsreceived 0.9% saline (Sal). At PN60, learning was evaluated true 10 days in an eight-armelevated maze and at PN120 retrograde memory. At PN60, MPH group showed a delay of61% in the latency, an increase of 100% in the number of errors and 200% in the number ofrepetition errors when compared to the Sal group, until the day 5 of learning period (p=0.004).After the washout period, at PN120, the MPH group showed an increase of 37% in thelatency, 49% in the number of errors of reference and 600% in the number of repetition errorscompared with the Sal group (p=0.001, p=0.004 and p=0.01). Exposure to MPH duringperipubertal phase decreases learning and memory in adult male Wistar rats.

Perinatal malnutrition has a devastation effect later in life. This study evaluated whetherprotein restriction in adolescent rats programs hypertension regarding cardiac dysfunction.CEUA approved the experimental protocol under nº 3353060421. 30-day-old Wistar male ratswere fed a low protein diet (4%) for the next thirty days and subsequently fed a 20.5% normalprotein diet for the next 60-days with normal diet (LP group). Control rats (NP group) werefed a normal protein diet throughout life. Cardiovascular system function was evaluated with120-days-old. Statistical analyses were performed with T-Student test. LP animals displayedan inferior body mass and nose-tail length (P=0.0001; P=0.01) and also rising retroperitonealfat (P=0.03). LP rats exhibited a higher in mean arterial blood pressure (p=0.05). In theechocardiogram, LP group showed an increased in the diameter (p=0.01, p=0.02),interventricular septum (p=0.040 e p=0.03) and the in posterior wall (p=0.01 e p=0.03) of theleft ventricle in diastole and systole respectively. Protein restriction in peripubertal periodleads to hypertension in adulthood, sustained by greater cardiac dysfunction.

Each stage (early, middle and late) of lactation is a critical period during which maternalmalnutritional can negatively effects on the offspring's body development. We investigatedthe effects of a maternal high fat diet (HF) during the different stages of lactation on bodyweight of male offspring at weaning. Female Wistar rats were fed either a HF diet only duringthe first week (HF1-7 group), second week (HF7-14 group), third week (HF14-21 group) andthroughout lactation (group HF1-21) or standard diet during all lactation. Biometricparameters of dams and male offspring were evaluated. HF fed dams did not have a differencein body weight, food intake and fat pad compared with the control dams. Regarding theoffspring, a higher final body weight was observed in males from the HF7-14 and HF14-21and HF21 groups compared to the control. There was an increase in retroperitoneal andmesenteric fat in HF21 and HF14-21 compared with control groups. Higher perigonadal fatpat was only observed in HF21. Consumption of maternal HF diet throughout lactation causeshigh body weight in male offspring. Interestingly, each isolated phase also causes importantbody weight accumulation, mainly the second and third week.

The current study investigate sound effects of low-protein diet (LP) during peripubertal periodto induce metabolic dysfunctions. In our study (CEUA 2910011021), 30 days-old Wistar malerats received LP (4% protein) and control rats were fed a 20.5% protein diet, for 60 days (NPgroup). Biometric parameters was taken and glucose, total and HDL-cholesterol, andtriglycerides were evaluated from plasma samples. Glycemia homeostasis was evaluated byOGTT and ITT, while hepatic parameters, including quantitative analysis of fat, triglyceridesand cholesterol in the liver was evaluated ex vivo. At 60 days, LP rats showed inferior bodymass (P=0.003), food intake (P=0.05), and nose-tail length (P=0.0001), compared to NP.Regarding biochemical assays, LP rats showed higher serum glucose (P=0.008); however,triglyceride (P=0.002), total cholesterol (P=0.02), and HDL levels (P