ATP-Induced Nuclear and Cytosolic Ca2+ Signal in Various Stages of Interphase HeLa/Fucci2 Cell

Cell cycle progression involves the coordination of growth, DNA replication and division in proliferating cells. These intracellular activities are linked with calcium signaling in which calcium ion (Ca2+) act as a second messenger or as an agent for phosphorylation processes. Previous studies have examined the Ca2+ in the dividing cells; however, none of these gave the detailed explanation on Ca2+ dynamics in an interphase cell. This study addresses here the issue of whether the nuclear and cytosolic Ca2+ concentrations ([Ca2+]n and [Ca2+]c) changes ar

The Effects of Diuretics on Intracellular Ca2+ Dynamics of Arteriole Smooth Muscles as Revealed by Laser Confocal Microscopy

The regulation of cytosolic Ca2+ homeostasis is essential for cells, including vascular smooth muscle cells. Arterial tone, which underlies the maintenance of peripheral resistance in the circulation, is a major contributor to the control of blood pressure. Diuretics may regulate intracellular Ca2+ concentration ([Ca2+]i) and have an effect on vascular tone. In order to investigate the influence of diuretics on peripheral resistance in circulation, we investigated the alteration of [Ca2+]i in testicular arterioles with respect to several categories of diuretics using real-time confocal laser scanning microscopy. In this study, hydrochlorothiazide (100 µM) and furosemide (100 µM) had no effect on the [Ca2+]i dynamics. However, when spironolactone (300 µM) was applied, the [Ca2+]i of smooth muscles increased. The response was considerably inhibited under either extracellular Ca2+-free conditions, the presence of Gd3+, or with a treatment of diltiazem. After the thapsigargin-induced depletion of internal Ca2+ store, the spironolactone-induced [Ca2+]i dynamics was slightly inhibited. Therefore, the spironolactone-induced dynamics of [Ca2+]i can be caused by either a Ca2+ influx from extracellular fluid or Ca2+ mobilization from internal Ca2+ store, with the former being dominant. As tetraethylammonium, an inhibitor of the K+ channel, slightly inhibited the spironolactone-induced [Ca2+]i dynamics, the K+ channel might play a minor role in those dynamics. Tetrodotoxin, a neurotoxic Na+ channel blocker, had no effect, therefore the spironolactone-induced dynamics is a direct effect to smooth muscles, rather than an indirect effect via vessel nerves

Effects of ATP and analogues on [Ca2+] dynamics in the rabbit corneal epithelium

岩手医科大学199