Book of Abstracts - New Frontiers 2022

Abstracts of oral presentations

STRESS, CATECHOLAMINES AND BETA3-ADRENERGIC RECEPTORS

D. Jezova, A. Puhova

Laboratory of Pharmacological Neuroendocrinology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia

Beta-adrenergic stimulation is known to be a significant regulatory mechanism in the heart. Beta3 subtype of adrenergic receptors localized in the heart may protect the myocardium against adverse effects of excessive catecholamine stimulation. Stimulation of cardiac beta3-adrenoceptors may lead to a decrease in heart contractility. In the adipose tissue, the main function of these receptors is to mediate lipolysis and thermogenesis. Their function in the brain is unclear. The sympathetic-adrenomedullary system is one of the two main stress systems. The action of catecholamines via beta-adrenoceptors is important under stress conditions. The stress-induced adrenaline and noradrenaline release depends on the type and intensity of the stress stimulus. We have tested the hypothesis that stress associated with the repeated immune challenge has an impact on beta3-adrenergic receptor gene expression in the adipose tissue and in the brain (1). Rats of both sexes were intraperitoneally treated with increasing doses of lipopolysaccharide (LPS) for 5 days. LPS treatment led to body weight loss, an increase in anxiety behavior, and a decrease in beta3-receptor gene expression in the white adipose tissue with higher values in males compared to females. In LPS-treated animals of both sexes, beta3-receptor gene expression was increased in the prefrontal cortex but not the hippocampus. Another chronic stressor evaluated was compulsory wheel running for three weeks (2). No changes in beta3-adrenergic receptor and cell proliferation measured by 5-bromo- 2´ -deoxyuridine incorporation in the left heart ventricle were observed in rats exposed to physical exercise compared to controls. In the brown adipose tissue, the gene expression of uncoupling protein-1 (UCP-1), which is an important mediator of thermogenesis, was increased. The gene expression of beta3-adrenergic receptors following prolonged wheel running increased in the white, while it decreased in the brown adipose tissue. The reduced beta3-adrenergic receptor but not enhanced uncoupling protein-1 gene expression supports the hypothesis of hypoactive brown adipose tissue in response to exercise. 1) Csanova A., Hlavacova N., Hasiec M., Pokusa M., Prokopova B., Jezova D.: β(3) -adrenergic receptors, adipokines and neuroendocrine activation during stress induced by repeated immune challenge in male and female rats. Stress. 20(3):294-302, 2017 2) *Balagova L., *Graban J., *Puhova A., Jezova D.: Opposite effects of voluntary physical exercise on β3 -adrenergic receptors in the white and brown adipose tissue. Hormone and Metabolic Research. 51(9): 608-617, 2019. *equally contributed

Keywords: autonomic nervous system, adipose tissue, heart

Funding: Supported by APVV-18-0283.

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