Methylphenidate clinically oral doses improved brain and heart glutathione redox status and evoked renal and cardiac tissue injury in rats

Lisdexamfetamine dimesylate-exposition in male rats during the peripubertal period impairs inflammatory mechanisms, antioxidant activity, and apoptosis process in kidneys of male pubertal rats

Lisdexamfetamine dimesylate (LDX) is a prodrug of dextroamphetamine, which has been widely recommended for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD). There are still no data in the literature relating the possible toxic effects of LDX in the kidney. Therefore, the present study aims to evaluate the effects of LDX exposure on morphological, oxidative stress, cell death and inflammation parameters in the kidneys of male pubertal Wistar rats, since the kidneys are organs related to the excretion of most drugs. For this, twenty male Wistar rats were distributed randomly into two experimental groups: LDX group-received 11,3 mg/kg/day of LDX; and Control group-received tap water. Animals were treated by gavage from postnatal day (PND) 25 to 65. At PND 66, plasma was collected to the biochemical dosage, and the kidneys were collected for determinations of the inflammatory profile, oxidative status, cell death, and for histochemical, and morphometric analyses. Our results show that there was an increase in the number of cells marked for cell death, and a reduction of proximal and distal convoluted tubules mean diameter in the group that received LDX. In addition, our results also showed an increase in MPO and NAG activity, indicating an inflammatory response. The oxidative status showed that the antioxidant system is working undisrupted and avoiding oxidative stress. Therefore, LDX-exposition in male rats during the peripubertal period causes renal changes in pubertal age involving inflammatory mechanisms, antioxidant activity and apoptosis process.

Evidence of methylphenidate effect on mitochondria, redox homeostasis, and inflammatory aspects: Insights from animal studies

Methylphenidate (MPH) is a central nervous system (CNS) stimulant known for its effectiveness in the treatment of Attention Deficit Hyperactivity Disorder (ADHD), a neuropsychiatric condition that has a high incidence in childhood and affects behavior and cognition. However, the increase in its use among individuals who do not present all the diagnostic criteria for ADHD has become a serious public health problem since the neurological and psychiatric consequences of this unrestricted use are not widely known. In addition, since childhood is a critical period for the maturation of the CNS, the high prescription of MPH for preschool children also raises several concerns. This review brings new perspectives on how MPH (in different doses, routes of administration and ages) affects the CNS, focusing on animal studies that evaluated changes in mitochondrial (bioenergetics), redox balance and apoptosis, as well as inflammatory parameters. MPH alters brain energy homeostasis, increasing glucose consumption and impairing the activity of enzymes in the Krebs cycle and electron transport chain, as well as ATP levels and Na⁺,K⁺-ATPase activity. MPH induces oxidative stress, increasing the levels of reactive oxygen and nitrogen species and altering enzymatic and non-enzymatic antioxidant defenses, which, consequently, is related to damage to proteins, lipids, and DNA. Among the harmful effects of MPH, studies also demonstrate its ability to induce inflammation as well as alter the apoptosis pathway. It is important to highlight that age, treatment time, administration route, and dose are factors that can influence MPH effects. However, young animals seem to be more susceptible to damage caused by MPH. It is possible that changes in mitochondrial function and markers of status oxidative, apoptosis and inflammation may be exerting important mechanisms associated with MPH toxicity and, therefore, the unrestricted use of this drug can cause brain damage.

Methylphenidate exerts neuroprotective effects through the AMPK signaling pathway

PURPOSE

Cerebral ischemia is the main cause of permanent adult disabilities worldwide. This study investigated the reparative effects and potential mechanisms of methylphenidate (MPH), a medication for the treatment of attention-deficit/hyperactivity disorder.

METHODS

In vitro oxygen-glucose deprivation/reperfusion (OGD/R) and in vivo cerebral ischemia-reperfusion models were established. Sprague-Dawley (SD) rats were randomly divided into four groups (n = 20): Sham, Model, and MPH (0.5 and 1 mg/kg). Rats in MPH groups were treated with 0.5 or 1 mg/kg MPH via intraperitoneal injection for 7 days. Rats in the Sham and Model groups were treated with PBS during the same period. Cell viability was measured using MTT assay. Apoptosis was detected by Annexin V/PI staining. Protein expression was detected by Western blot. The volume of cerebral infarction was detected by triphenyltetrazolium chloride (TTC) staining. The DNA damage in ischemic brain tissues was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.

RESULTS

MPH treatment significantly reduced OGD/R-induced cell damage, shown by the increased cell viability and decreased apoptotic rate. p-AMPK and p-ACC protein expression increased in the OGD/R model after MPH treatment. The addition of AMPK inhibitor largely abolished the neuroprotective effects of MPH, evidenced by the reduced cell viability, increased apoptotic rate, and decreased protein expression of p-AMPK as well as p-ACC. Moreover, MPH treatment significantly alleviated the cerebral ischemia-reperfusion injury and decreased apoptosis in brain tissues, which may be associated with the AMPK/ACC pathway.

CONCLUSIONS

MPH exerted protective activities against oxidative stress in the OGD/R model and ameliorated brain damage of rats in the middle cerebral artery occlusion model, at least in part, through activating the AMPK pathway. These data demonstrated neuroprotective properties of MPH and highlighted it as a potential therapeutic agent against cerebral ischemia-reperfusion injury.

Toxicology of long-term and high-dose administration of methylphenidate on the kidney tissue - a histopathology and molecular study

The present study aims to assess the influences of oral methylphenidate on kidney function and structure versus vehicle treatment in adult male rats. In this study, thirty adult male rats equally into two treatment groups divided randomly, and among them, MPH has been administered for 21 days, at doses of 20 mg/kg, and the control group has received salin. In renal, under the effect of MPH applying quantitative real-time PCR, we analyzed nephrotoxicity-related molecular pathways like autophagy, inflammation, and apoptosis. Moreover, the levels of GSH, CAT, and SOD were investigated as antioxidant enzymes. Afterward, stereological analysis in MPH-treated rats has been performed. Analysis of qPCR displayed inflammation, impaired autophagy, and enhanced apoptosis with histological changes in the kidney's tissue, also an important rise in the antioxidant enzymes' level. Besides, 20 mg/kg of MPH led to a decline in the mean of Bowman's space thickness and renal corpuscle's volume in comparison to the control rats. Collectively, our histological and molecular data implicit that in the kidney region, administrating of MPH evoked discriminative expression alterations in nephrotoxicity-associated signaling cascades, specifically autophagy, inflammation, and apoptosis paired with important damage to kidney tissue.

The Effect of Methylphenidate and Aerobic Exercise on Renal Function of Male Rats

Introduction: Inadequate awareness and knowledge exists regarding the effects of stimulant drugs on renal health among athletes. The present study aimed to determine the effects of methylphenidate, as a stimulant drug, and aerobic exercise on renal function in rats. Materials and Methods: Eighty male rats were randomly divided into 8 groups (n=10 per group) including control (Co), aerobic exercise sham (AE Sh), drug sham (D Sh), aerobic exercise (AE), the effective dose of drug (ED, 10 mg/kg), 3 times of effective dose (TED, 30 mg/kg), aerobic exercise-effective dose (AE-ED), and aerobic exercise-three times of effective dose (AE-TED). The drug was orally administrated to the animals, and then they were placed on a rat treadmill after 30 minutes. The physical activity (25 m/min) was performed 30 minutes a day, 3 days a week for two months. Twenty-four hours after the last session of AE, blood samples were taken from the rats and serum creatinine (Cr) and blood urea nitrogen (BUN) were determined. Results: The results showed that serum Cr and BUN levels were not significantly different in the exercise group compared to the control groups (i.e., Co, AE Sham, and D Sham). However, serum BUN and Cr significantly increased in the AE-ED and AE-TED groups compared to the AE group (PCr=0.001 and PBUN=0.001). Conclusion: In general, significant increases in the serum BUN and Cr levels in rats received methylphenidate indicated decreased renal function in these animals.

The Intersection of Central Dopamine System and Stroke: Potential Avenues Aiming at Enhancement of Motor Recovery

Dopamine, a major neurotransmitter, plays a role in a wide range of brain sensorimotor functions. Parkinson's disease and schizophrenia are two major human neuropsychiatric disorders typically associated with dysfunctional dopamine activity levels, which can be alleviated through the druggability of the dopaminergic systems. Meanwhile, several studies suggest that optimal brain dopamine activity levels are also significantly impacted in other serious neurological conditions, notably stroke, but this has yet to be fully appreciated at both basic and clinical research levels. This is of utmost importance as there is a need for better treatments to improve recovery from stroke. Here, we discuss the state of knowledge regarding the modulation of dopaminergic systems following stroke, and the use of dopamine boosting therapies in animal stroke models to improve stroke recovery. Indeed, studies in animals and humans show stroke leads to changes in dopamine functioning. Moreover, evidence from animal stroke models suggests stimulation of dopamine receptors may be a promising therapeutic approach for enhancing motor recovery from stroke. With respect to the latter, we discuss the evidence for several possible receptor-linked mechanisms by which improved motor recovery may be mediated. One avenue of particular promise is the subtype-selective stimulation of dopamine receptors in conjunction with physical therapy. However, results from clinical trials so far have been more mixed due to a number of potential reasons including, targeting of the wrong patient populations and use of drugs which modulate a wide array of receptors. Notwithstanding these issues, it is hoped that future research endeavors will assist in the development of more refined dopaminergic therapeutic approaches to enhance stroke recovery.