Ameliorating the Role of Aripiprazole in Memory Deficits Induced by Intracerebroventricular Streptozotocin-Induced Dementia of Alzheimer's Type

Pharmacokinetic validation of a new protocol of chronic oral administration of aripiprazole in male C57 Bl/6 mice through drinking solution

Schizophrenia is a chronic mental illness, with a prevalence of about 1%. The symptoms are classified in three categories: positive symptoms, negative symptoms and deficits in cognitive function. Regarding the pharmacological treatment, current antipsychotics mainly improve positive symptoms while negative and cognitive symptoms remain inadequately treated. Among them, aripiprazole, through its pharmacological properties results in regulation of positive symptoms and, to a lesser extent, to negative and cognitive ones. Drug treatment studies in animals typically employ administration methods such as injection or gavage, which is time-consuming over long periods, does not reflect route of administration used in patients, and cause substantial stress in animals. We assessed herein the pharmacokinetic properties and behavioural effects of aripiprazole after chronic administration via drinking solution in C57Bl/6 mice. Results show that subchronic administration of 1 and 10 mg/kg doses of aripiprazole via drinking solution present significant blood concentrations, without any significant effect on the spontaneous activity of mice (between 10 a.m. and 3 p.m.). Furthermore, we described for the first time to our knowledge the main pharmacokinetic parameters of aripiprazole after gavage acute administration (10 mg/kg). Collectively, all of these data will be very useful in future projects including chronic administrations (several months) of this antipsychotic.

Administration of Aripiprazole Alleviates Memory Impairment and Restores Damaged Glutamatergic System in 5xFAD Mice

PURPOSE

Many patients with Alzheimer's disease (AD) also have psychosis, and it has been reported that these patients have more severely impaired cognitive functions than patients without psychosis. The glutamatergic system in the brain is known to play an important role in memory and learning in the neural circuits. However, there has been limited research on how antipsychotic drugs affect the glutamatergic system of AD. Therefore, we aimed to investigate the effects of aripiprazole on the glutamatergic system in an animal model of AD using functional molecular imaging.

PROCEDURES

In this study, 5xFAD mice were used as the animal model. At the age of 5 months, the mice were divided into wild-type, vehicle control, and aripiprazole-treated groups (n = 6 per group). The aripiprazole-treated group was administered aripiprazole for 2 months at a dose of 1 mg·kg-1·day-1. At 7 months of age, the animals underwent behavioral tests and glutamate positron emission tomography (PET) scans.

RESULTS

The aripiprazole-treated group exhibited alleviated memory impairment in a novel object recognition test. Moreover, this group displayed 7-8% higher binding in the glutamate PET scan than the vehicle-treated 5xFAD group. Postmortem examination confirmed the recovery of glutamatergic damage.

CONCLUSIONS

The administration of aripiprazole alleviated memory impairment and restored the damaged glutamatergic system in 5xFAD mice. Although the use of aripiprazole in AD patients may be a constraint in terms of safety, we confirmed the possibility that the administration of antipsychotic drugs can be effective in AD.

Aripiprazole Attenuates Cognitive Impairments Induced by Lipopolysaccharide in Rats through the Regulation of Neuronal Inflammation, Oxidative Stress, and Apoptosis

Background and Objectives: Aripiprazole (APZ), an atypical antipsychotic, is mainly prescribed for conditions such as schizophrenia and bipolar disorder, while ongoing research indicates promising neuroprotective qualities. APZ's mechanism of action, involving the regulation of neurotransmitter levels, appears to contribute to its potential to shield neural tissues from specific forms of harm and degeneration. Materials and Methods: To investigate its neuroprotective mechanisms, groups of rats were orally administered APZ at 1 or 2 mg/kg once daily for a 30-day period. In addition, neuronal toxicity was induced through intraperitoneal injection of four doses of lipopolysaccharide (LPS) at a concentration of 1 mg/kg. To evaluate cognitive function, particularly, short-term recognition memory, the procedure implemented the novel object recognition (NOR) task. Subsequently, brain tissues were gathered to examine markers linked with neuroinflammation, oxidative stress, and apoptosis. Results: The administration of LPS led to a decline in memory performance during the NOR tasks. Simultaneously, this LPS treatment raised inflammatory markers like cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, and nuclear factor kappa B (NF-κB), increased oxidative markers such as malondialdehyde (MDA), and triggered apoptosis markers like Caspase-3 and Bcl2 associated X protein (Bax) within the brain. Furthermore, it decreased levels of antioxidants like reduced glutathione (GSH) and catalase, as well as the anti-apoptotic marker B-cell lymphoma (Bcl)-2 in brain tissue. The use of APZ resulted in enhanced recognition memory performance, as indicated by improved exploration and discrimination abilities of the objects in the NOR task. Moreover, APZ lowered the markers associated with neuronal vulnerability, such as COX-2, NF-κB, MDA, Caspase-3, and Bax. Additionally, it increased the levels of protective markers, including GSH, catalase, and Bcl-2 in LPS-challenged brains. Conclusions: In summary, the findings suggest that APZ exhibits protective properties against neuronal inflammation, oxidative stress, and apoptosis markers in the context of inflammatory-related neurodegeneration. Additional in-depth investigations are needed to further explore potential applications.