B radykinin Receptor-Meadiated Intracellular Calcium Mobilization and ATP Changes in Cultured Bovine Corneal Endothelial Cell

To clarify the effect of bradykinin(Bk)on cultured bovine corneal endothelial cells(BCEC), cytosolic free calcium([Ca2+])mobilization and cell proliferation were investigated. The [Ca2+] was determined using a Ca2+ sensitive indicator, Fura-2/AM, and cell proliferation was evaluated by counting the cell number. Bk induced the transient increase of [Ca2+] in a concentration-dependent manner(10(-11)M~10(-7)M)and its 50% effective concentration was about 5x10(-11)M. The basal [Ca2+] with 1mM CaCl2 in the bathing solution was 87+/-9nM. Transient Bk(10(-8)M)-induced [Ca2+] increase was inhibited slightly but significantly by the pretreatment with EGTA. The pretreatment with U-73122(5x10(-6)M), an inhibitor of phospholipase C, also attenuated Bkinduced [Ca2+] mobilization. To identify and characterize the Bk receptor subtype in BCEC, Bk1 and Bk2 antagonists were investigated. Transient Bk(10(-8)M)-induced [Ca2+] increase was almost absolutely attenuated by the pretreatment with Bk2 antagonist for 10 minutes. To investigate the physiological effect of Bk, Bk-induced mitogenic effect was studied. 10(-8)M of Bk produced significant increase of intracellular ATP levels from the day 2 to the day six of culture period. This Bk-induced mitogenic effect was inhibited by the treatment with Bk2 antagonist. Bk-induced ion transport was determined by measuring intracellular ATP contents. Intracellular ATP content([ATP]i)was decreased by the treatment with 10(-8)M Bk for 10 minutes. Bk-induced [ATP]i decrement was significantly restored by the pretreatment with ouabain for 30 minutes. In summary, stimulation of intracellular signal transduction by Bk in BCEC is coupled with Bk2 type receptor. And also, Bk produces mitogenic effect and enhancesion and fluid transport in BCEC.

Mitogenic effects of nicotine to human periodontal ligament(PDL) cells in vitro / 대한치과교정학회지

Nicotine is one of the major components of cigafette smoking which causes various systemic and local diseases to human body. Mitrogenic effects of nicotine to systemic disease are interesting factors in the results of cellular proliferation especially to vascular and pulminary tissus or cells. The study of local effects concerns with destruction of tissue and delayed healing rate after various surgicla treatment. Platelet-Derived Growth factor(PDGF) and Insulin-like growth factor(IGF) are known as major mitogens to human PDL cells. The purpose of this studywas to investgate the mitogenic effects of nicotine to human PDL cells. We studied the expression of PDGF-alpha receptor, PDGF-betareceptor, and IGF-1 receptor mRNA form the nicotine treated human PDL cells by northern analysis. The experimental groups were divided into different serum(1%, 10%) and nicotine(100ng/ml, 1000ng/ml) condentrations and each group was studied by time course. The results of this study showed upregulation of PDGF-alpha, beta receptor and IGF-1 receptor mRNA at 100ng/ml nicotine concentration and 10% serum group to the time course. These results suggest that physiologically attainable nicotine concentrations may stimulate mitogenic gene synthesis to human PDL cells in vitro.