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pubmed:abstractText |
To investigate the effect of nucleotides on cytosolic free calcium mobilization and proliferation activity in HaCaT keratinocytes, nucleotides-induced intracellular free calcium concentration ([Ca(2+)](i)) and cell proliferation observed. [Ca(2+)](i) to the extracellular nucleotides was determined using Ca(2+) sensitive indicator, Fura-2/AM with digital video fluorescence imaging microscopy, and cell proliferation was evaluated by counting of cell number. An adenosine 5'-triphosphate (ATP)-induced [Ca(2+)](i) increase was observed from the concentration of 10(-8) M and was more conspicuous at higher concentrations in a concentration-dependent manner. Additionally, other nucleotides such as ADP, UTP, and 2-me-S-ATP also induced a [Ca(2+)](i) increase in a concentration-dependent manner. However, adenosine induced a slight increase of [Ca(2+)](i) only at 10(-3) M. alpha,-methylene-ATP did not evoke any rise in [Ca(2+)](i). The maximal response observed occurred with ATP and UTP at a concentration of 10(-4) M. The ATP-induced transient [Ca(2+)](i) increase was attenuated by the pretreatment with phospholipase C (PLC) inhibitor, U-73122 (10 microM) for 30 min. ATP-induced [Ca(2+)](i) increase and cell proliferation were inhibited by putative P2Y receptor antagonist, suramin (10(-4) M). When the HaCaT cells were stimulated with nucleotides on a concentration of 10(-4) M and cultured for 5 days, the order of effect on cell proliferation was observed to be ATP>UTP>ADP>2-me-S-ATP. Based on these results, we suggest that extracellular ATP stimulate HaCaT keratinocytes proliferation via purinoceptor-mediated [Ca(2+)](i) mobilization
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pubmed:affiliation |
Department of Pharmacology, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-040, South Korea.
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