Receptors, Volume 3, Issue 2 (June 2024) – 5 articles

The constant use of alcoholic beverages can deregulate serotonin levels, affecting neurotransmitters and triggering symptoms of anxiety. In this context, the objective of this work was to evaluate the anxiolytic potential and possible action mechanisms of the natural compound amentoflavone against the deleterious effects caused by alcohol withdrawal on the behavior of adult zebrafish (aZF). The experiments showed that amentoflavone did not change locomotion and did not cause toxicity in aZF during up to 96 h of analysis, with a median lethal concentration (LC₅₀) greater than 1.0 mg/mL. The reversal of anxiety by pretreatment with granisetron suggested that the anxiolytic effect of amentoflavone is dependent on serotonergic 5-HT_3A/3B receptors. Furthermore, amentoflavone reversed anxiety due to flumazenil pretreatment, suggesting a dependence on the GABA_A receptor. The three concentrations of amentoflavone tested were effective in treating anxiety resulting from alcohol withdrawal. In silico analysis validated the in vivo results, supporting the idea that the interaction of amentoflavone with the protein occurs in a more stable manner than reference compounds. Amid growing interest in natural alternatives to treat anxiety disorders, amentoflavone is a potential candidate for a new anxiolytic compound that acts specifically on the 5HT_3A/3B and GABAergic serotonergic pathways. Full article

Estrogen receptor (ER) β (ERβ) is the second ER subtype that mediates the effects of estrogen in target tissues along with ERα that represents a validated biomarker and target for endocrine therapy in breast cancer. ERα was the only known ER subtype until 1996 when the discovery of ERβ opened a new chapter in endocrinology and prompted a thorough reevaluation of the estrogen signaling paradigm. Unlike the oncogenic ERα, ERβ has been proposed to function as a tumor suppressor in breast cancer, and extensive research is underway to uncover the full spectrum of ERβ activities and elucidate its mechanism of action. Recent studies have relied on new transgenic models to capture effects in normal and malignant breast that were not previously detected. They have also benefited from the development of highly specific synthetic ligands that are used to demonstrate distinct mechanisms of gene regulation in cancer. As a result, significant new information about the biology and clinical importance of ERβ is now available, which is the focus of discussion in the present article. Full article

Understanding the intricate role of dopamine D1–D5 receptors is pivotal in addressing the challenges posed by the aging global population, as well as by social stress and advancing therapeutic interventions. Central to diverse brain functions such as movement, cognition, motivation, and reward, dopamine receptors are ubiquitously distributed across various brain nuclei. This comprehensive review explores the nuanced functions of each dopamine receptor, D1, D2, D3, D4, and D5, in distinct brain regions, elucidating the alterations witnessed in several neurological and psychiatric disorders. From the substantia nigra and ventral tegmental area, crucial for motor control and reward processing, to the limbic system influencing emotional responses, motivation, and cognitive functions, each brain nucleus reveals a specific involvement of dopamine receptors. In addition, genetic variations in dopamine receptors affect the risk of developing schizophrenia and parkinsonism. The review further investigates the physiological significance and pathogenic impacts of dopamine receptors in critical areas like the prefrontal cortex, hypothalamus, and striatum. By unraveling the complexities of dopamine receptor biology, especially those focused on different brain nuclei, this review provides a foundation for understanding their varied roles in health and disease, which is essential for the development of targeted therapeutic strategies aimed at mitigating the impact of aging and mental health on neurological well-being. Full article

Neuroendocrine tumors (NETs) represent a diverse group of neoplasms originating from neuroendocrine cells, presenting varied clinical behaviors and posing significant challenges in management. This review explores the emerging roles of receptor tyrosine kinases (RTKs) in the pathogenesis and progression of NETs, including vascular endothelial growth factor receptors (VEGFRs), insulin-like growth factor receptors (IGF-1R), RET, epidermal growth factor receptor (EGFR), and ALK. The dysregulation of RTK signaling pathways contributes to key cellular processes such as proliferation, survival, and invasion in NETs. We discuss the potential of targeting RTKs as therapeutic strategies in NETs, with a focus on recent developments in RET inhibitors and the therapeutic implications of RTK alterations. Full article

Recent research has emphasized the potential of natural and synthetic cannabinoids as anticancer agents. Yet it remains unclear whether and in which sense cannabinoids affect the anticancer activity of NK cells, an important branch of anticancer immunity. Similar uncertainty exists regarding NK cells-based immunotherapy. Here we presented an overview of multiple cannabinoid targets as canonical (mainly CB2) and non-canonical receptors, ion channels, transporters, and enzymes, expressed in NK cells, along with underlying molecular mechanisms. Through them, cannabinoids can affect viability, proliferation, migration, cytokine production, and the overall anticancer activity of NK cells. Respective holistic studies are limited, and, mostly, are phenomenological, not linking observed effects with certain molecular targets. Another problem of existing studies is the lack of standardisation, so that diverse cannabinoids at variable concentrations and ways of administration are applied, and often, instead of purified NK cells, the whole lymphocyte population is used. Therefore, there is an urgent need for more focused, systemic, and in-depth studies of the impact of the cannabinoid toolkit on NK cell function, to critically address the compatibility and potential synergies between NK activity and cannabinoid utilization in the realm of anticancer interventions. Full article