Lipoic acid prevents mirtazapine-induced weight gain in mice without impairs its antidepressant-like action in a neuroendocrine model of depression

Mirtazapine Improves Locomotor Activity and Attenuates Neuropathic Pain Following Spinal Cord Injury in Rats via Neuroinflammation Modulation

Neuroinflammation-related locomotor deficits and neuropathic pain are expected outcomes of spinal cord injury (SCI). The atypical antidepressant mirtazapine has exhibited potential neuroprotective and anti-inflammatory effects. This research aims to investigate the impacts of mirtazapine on post-SCI neuropathic pain and locomotor recovery, with a particular focus on neuroinflammation. The study utilized 30 male Wistar rats divided into five groups: Sham, SCI with vehicle treatment, and SCI administered with mirtazapine (3, 10, and 30 mg/kg/day, ip, for one week). Locomotor activity was assessed using the Basso, Beattie, and Bresnahan (BBB) scale. Mechanical, thermal, and cold allodynia were assessed using von-Frey filaments, tail flick latency, and the acetone test, respectively. ELISA was utilized to measure cytokines, while Western blotting was used to determine TRPV1 channel, 5-HT2A receptor, NLRP3, and iNOS expression. Histopathological analyses were also examined, including hematoxylin and eosin (H&E) and Luxol fast blue (LFB) staining. Mirtazapine (10 and 30 mg/kg/day) significantly improved locomotor recovery according to BBB score. It attenuated mechanical, thermal, and cold allodynia post-SCI. Moreover, it decreased pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and IL-18, while increasing anti-inflammatory cytokine IL-4 and IL-10. Furthermore, it downregulated iNOS, NLRP3, and TRPV1 expression and upregulated the 5-HT2A receptor. H&E and LFB staining further revealed attenuated tissue damage and decreased demyelination. Our findings suggest that mirtazapine can alleviate neuropathic pain and reinforce locomotor recovery post-SCI by modulating neuroinflammatory responses, NLRP3, iNOS, TRPV1 channel, and 5-HT2A receptor expression.

Psychotropic Drug-Related Weight Gain and Its Treatment

Psychotropic drug-related weight gain (PDWG) is a common occurrence and is highly associated with non-initiation, discontinuation, and dissatisfaction with psychiatric drugs. Moreover, PDWG intersects with the elevated risk for obesity and associated morbidity that has been amply reported in the psychiatric population. Evidence indicates that differential liability for PDWG exists for antipsychotics, antidepressants, and anticonvulsants. During the past two decades, agents within these classes have become available with significantly lower or no liability for PDWG and as such should be prioritized. Although lithium is associated with weight gain, the overall extent of weight gain is significantly lower than previously estimated. The benefit of lifestyle and behavioral modification for obesity and/or PDWG in psychiatric populations is established, with effectiveness similar to that in the general population. Metformin is the most studied pharmacological treatment in the prevention and treatment of PDWG, and promising data are emerging for glucagon-like peptide-1 (GLP-1) receptor agonists (e.g., liraglutide, exenatide, semaglutide). Most pharmacologic antidotes for PDWG are supported with low-confidence data (e.g., topiramate, histamine-2 receptor antagonists). Future vistas for pharmacologic treatment for PDWG include large, adequately controlled studies with GLP-1 receptor agonists and possibly GLP-1/glucose-dependent insulinotropic polypeptide co-agonists (e.g., tirzepatide) as well as specific dietary modifications.