With fluorescence microscopy, it was revealed that a decrease in the concentration of extracellular calcium ([Ca2+]ex) results in two types of Ca2+-responses in white adipocytes: Ca2+-oscillations and transient Ca2+-signals. Activation of connexin hemichannels is involved in the mechanism of generation of Ca2+-oscillations, since the blockers of connexin hemichannels - carbenoxolone, octanol and proadifen, as well as Cx43 gene knock-down lead to complete suppression of these signals. TIRF

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... copy confirmed activation of Cx-43 in response to the reduction of [Ca2+]ex. In response to the activation of Cx-43, the secretion of ATP-containing vesicles from adipocytes occurs. And this ATP release is suppressed in adipocytes along with the Cx43 gene knock-down and is inhibited by Bafilomycin A1, a vacuolar ATPase inhibitor. At the level of intracellular signaling, the generation of Ca2+-oscillations in white adipocytes in response to a decrease in [Ca2+]ex takes place due to the mobilization of Ca2 + ions from the thapsigargin-sensitive Ca2+-pool in the endoplasmic reticulum via IP3R as a result of the activation of P2Y1 purinergic receptors and the phosphoinositide signaling pathway. Such paracrine activation of white adipose tissue in response to the opening of Cx43 hemichannels leads to local signal propagation and regulation of gene expression. At 24 hours after activation of Cx-43 and generation of Ca2+-oscillations in white adipocytes, there is a change in the expression of key genes involved in the regulation of lipolysis, which is accompanied by a decrease in the number of adipocytes that contained lipid droplets. Meanwhile, inhibition or knock-down of Cx-43 leads to inhibition of lipolysis and accumulation of lipid droplets. In this study, we elucidate and research the mechanism of generation of Ca2+-oscillations in white adipocytes in response to decreased concentration of Ca2 + ions in the external environment and show the correlation between periodic Ca2+-modes and lipolysis/lipogenesis balance regulation.