CNS & Neurological Disorders - Drug Targets (Formerly Current Drug Targets - CNS & Neurological Disorders) - Volume 24, Issue 9, 2025

Opioid addiction is a condition of the central nervous system that occurs as a result of using opiate-based substances, which can be either natural or synthetic chemicals. These have effects identical to those of morphine and work by interacting with opioid receptors such as morphine, heroin, opium, buprenorphine, and Oxycontin. Dopamine has been suggested to play a role in the mechanisms linked to opioid addiction. Additionally, neurotransmitters such as serotonin, norepinephrine, glutamate, and GABA may also have a significant impact. These processes play a critical role in the formation of brain circuits that are involved in the development of addictive behavior. The PI3K-Akt-mTOR pathway is widely recognized as an essential regulator of the effects induced by neurotransmitters on synaptic plasticity, protein synthesis, and cellular responses. This interplay has considerable importance in the development and persistence of opioid addiction, impacting several domains, including reward processing, stress reactivity, and brain plasticity. The understanding of these neurochemical modifications provides vital insights into the underlying mechanisms of addiction and presents potential pathways for treatments. The review enlisted the clinical trials of different types of opioid addiction or dependence. The review offers a succinct summary of many studies that establish a correlation between the PI3K/Akt-mTOR signaling pathway and various receptors implicated in multiple forms of opioid-related dependency.

Inorganic fluoride is widely used in dental practices to treat problems like dental caries and prevent bone-related issues. Exposure to excess amounts of fluoride both through drinking water or other sources impairs vital functions of the body and can prove to be toxic, especially for the central nervous system. Sodium fluoride (NaF) crosses the blood-brain barrier in early developmental stages and causes impairments related to learning and memory, anxiety, decreased locomotor ability, and in some cases, depression-like behaviour, especially in children. Major mechanisms involved in this toxicity include reduction in levels of nicotinic and muscarinic receptors, autophagy, and apoptosis in neurons, decreased glucose consumption, inhibition of enzymes involved in the generation of energy and transmission of the synapse, mitochondrial dysfunction, and increased oxidative stress leading to inflammation and neuronal cell death. Out of all these, an increase in oxidative stress was reported to be one of the main mechanisms of fluoride-induced neurotoxicity. Based on these inferences, various natural compounds having antioxidant properties, like curcumin, aloe vera, quercetin, epigallocatechin gallate, etc. have been studied for their protective role in sodium fluoride-induced neurotoxicity. Involvement of other pathways like Nrf2/Keap pathways, SIRT3, etc., have warranted a need for further detailed study to identify other potential therapeutic targets like AMPK to prevent/treat fluoride-induced neurotoxicity. The present review captures fluoride, its role in neurodevelopment, and mechanisms & pathways involved by which fluoride can hurt neurodevelopment & how AMPK can be a possible therapeutic target.

The most common neurodegenerative illness and leading cause of death in the world is Alzheimer's disease (AD), which is extremely expensive to treat. None of the AD treatments that are currently in the market with approval have any effect on disease progression. However, numerous clinical studies aimed at reducing amyloid beta (Aβ) plaque development, boosting Aβ clearance, or reducing neurofibrillary tangle (NFT) failed or had conflicting results. As oxidative stress (OS), mitochondrial dysfunction, and chronic neuroinflammation are implicated in numerous interconnected vicious cascades, research has revealed new therapeutic targets, including enhancing mitochondrial bioenergetics and quality control, reducing oxidative stress, or modulating neuroinflammatory pathways. This review examines the role of oxidative stress (OS), mitochondrial dysfunction, neuroinflammation, and the interplay between peripheral and central immune systems in the pathogenesis of AD. We highlight how OS and immune dysregulation drive chronic neuroinflammation, exacerbating AD progression. Immune cells and inflammatory molecules emerge as critical players in disease pathology. Overall, this review concludes that targeting OS and immune system crosstalk represents promising therapeutic strategies for mitigating AD progression, providing a foundation for future interventions.