Physiological role of calcium wave and capacitative calcium current in mammary epithelial cells

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It is well known that in various cells, mechanical stimulation caused transient increase of the intracellular calcium concentration and secretion of nucleotides, such as ATP, UTP and UDP.Released nucleotides induce spreading calcium wave in adjacent cells. The largest source of calcium is the smooth endoplasmic reticulum, and also there are capacitative calcium influx, and mitochondria. In this project, we cleared the presence of the intercellular communication between mammary secretary epithelial cells and mammary myoepithelial cells, via calcium wave. In the early of this project, we reported the increase of capacitative calcium current in the proliferation in early pregnant stage.We analysed the outward current stimulated by nucleotide, and by the activation of calcium-induced potassium channel. Recently, we concluded that there is another inward current, induced by same agonist. We concluded that this is due to the activation of Cl channel. Moreover, UTP induced ATP release inhibited by blocker of Cl channel, nifulmic acid. It is possible that intracellular ATP released to the extracellular fluid via some Cl channel. We tackled to the recording of single channel activity using inside out patch clamp, with ATP in both inside and outside. In the present, we could not reach any conclusion of presence of Cl/ATP channel. We cloned ClC3 channel gene in mammary tumor cell line, A23587, and transfected it in the neuroblastoma/glioma cell line, NG108-15. There was no difference in the action potential with overexpression of ClC3.