The aim of this experimental study was to evaluate micro- and ultrastructural changes of the carotid sinus wall during oral consumption of low doses of monosodium glutamate (MG) and following its withdrawal. Adult male albino rats (n=39) were enrolled into the study. Carotid sinus wall morphology was assessed by light and electron microscopy at the end of week 4 and week 8 of MG oral consumption, as well as 2 weeks after its withdrawal; the results were compared with the control group. After 8 weeks of MG consumption, the wall of the carotid sinus was disorganized, endothelial layer of intima deformed, often without clear margins, the media edematous and dissected with thickened elastic membranes, and the cells of the vascular wall were showing signs of apoptosis while extra fat was present in the adventitia. Upon discontinuation of MG after 4 weeks of its consumption, the structural organization of carotid sinus wall was partially preserved, whereas no compensatory processes were registered after 8 weeks of MG administration followed by 2 weeklong withdrawal. Therefore, 8-week-long lowdose MG consumption resulted in pronounced changes of the micro- and ultra-structure of the carotid sinus wall of albino rats. Discontinuation of MG following 4 weeks of its administration partially improved the morphologic characteristics of the carotid sinus wall within 2 weeks. Withdrawal of MG after 8 weeks of its administration did not result in any improvement of the micro- and ultra-structure of the carotid sinus wall within 2 weeks.

Metabolic physiology plays a key role in maintaining our health and resilience. Metabolic disorders can lead to serious illnesses, including obesity. The pathogenesis of the new long COVID syndrome in individuals with long-term recovery after SARS-Co-2 infection is still incomplete. Thus there is growing attention in the study of adipose tissue activities, especially brown adipose tissue (BAT) and associated resilience which plays a crucial role in diferent types of obesity as potential targets for pharmacologic and nutritional interventions in the context of obesity and long COVID. The number of studies examining mechanisms underlying BAT has grown rapidly in the last 10 years despite of role of BAT in individuals with COVID-19 and long COVID is modest. Therefore, this review aims to sum up data examining BAT activities, its resilience in health, obesity, and the possible link to long COVID. The search was conducted on studies published in English mostly between 2004 and 2022 in adult humans and animal models. Database searches were conducted using PubMed, Scopus, and Google Scholar for key terms including adipose tissue, BAT, adipokines, obesity, VPF/VEGF, and pathogenesis. From the initial search through the database were identifed relevant articles that met inclusion and exclusion criteria and our data regarding adipose tissues were presented in this review. It will discuss adiposity tissue activities. Current literature suggests that there are BAT integral efects to whitening and browning fat phenomena which refect the homeostatic metabolic adaptive ability for environmental demand or survival/adaptive mechanisms. We also review neural and vascular impacts in BAT that play a role in resilience and obesity. Finally, we discuss the role of BAT in the context of long COVID in basic research and clinical research.