Stimulation of single Ehrlich ascites tumor cells with agonists (bradykinin, thrombin) and with arachidonic acid (AA) induces increases in the free intracellular Ca2+ concentration ([Ca2+]i) in the presence and absence of extracellular Ca2+, measured using the Ca2+-sensitive probe fura 2. Sequential stimulation with two agonists elicits sequential increases in [Ca2+]i, unlike addition of the sa...

Histamine H1 receptors mediate activation of phospholipase C, with subsequent increases in cytosolic Ca2+ concentration ([Ca2+]i), and H2 receptors mediate accumulation of cAMP. HL-60 promyelocytes possess H2 receptors, but it is not known whether these cells also possess H1 receptors. We studied the effects of histamine on [Ca2+]i and the functional importance of histamine receptors in HL-60 p...

Increases in postsynaptic [Ca2+]i can result from Ca2+ entry through ligand-gated channels or voltage-gated Ca2+ channels, or through release from intracellular stores. Most attention has focused on entry through the N-methyl-D-aspartate (NMDA) receptor in causing [Ca2+]i increases since this pathway requires both presynaptic stimulation and postsynaptic depolarization, making it a central comp...

Asthma is characterized by airway inflammation and airflow obstruction from human airway smooth muscle (HASM) constriction due to increased local bronchoconstrictive substances. We have recently found bitter taste receptors (TAS2Rs) on HASM, which increase [Ca2+]i and relax the muscle. We report here that some, but not all, TAS2R agonists decrease [Ca2+]i and relax HASM contracted by G-protein ...

An oocyte of the marine bivalve Mytilus edulis, which is arrested at metaphase I, reinitiates meiosis at fertilization. The fertilized oocyte shows increases in intracellular Ca2+ ([Ca2+]i) comprising three different phases: an initial large [Ca2+]i transient, a subsequent low but sustained [Ca2+]i elevation, and repetitive small [Ca2+]i transients. In this study, we have investigated the sourc...

To survive, plants must respond rapidly and effectively to various stress factors, including biotic and abiotic stresses. Salinity stress triggers the increase of cytosolic free Ca2+ concentration ([Ca2+]i) via Ca2+ influx across the plasma membrane, as well as bacterial flg22 and plant endogenous peptide Pep1. However, the interaction between abiotic stress-induced [Ca2+]i increases and biotic...

Sei-hai-to (TJ-90, Qing Fei Tang), a Chinese traditional medicine, increases ciliary beat frequency (CBF) and ciliary bend angle (CBA) mediated via cAMP (3',5'-cyclic adenosine monophosphate) accumulation modulated by Ca2+-activated phosphodiesterase 1 (PDE1A). A high concentration of TJ-90 (≥40 μg/mL) induced two types of CBF increases, a transient increase (an initial increase, followed by a ...

Na(+)-Ca2+ exchange is proposed to be an important regulator of myoplasmic intracellular Ca2+ concentration ([Ca2+]i) and contraction in vascular smooth muscle. We investigated the role of Na(+)-Ca2+ exchange in regulating [Ca2+]i in swine carotid arterial tissues that were loaded with aequorin to allow simultaneous measurement of [Ca2+]i and force. Reversal of Na(+)-Ca2+ exchange, by reduction...

Fura 2 microfluorometry and perforated-patch whole cell recording were carried out simultaneously to investigate the relationship between intracellular free Ca2+ concentration ([Ca2+]i) and membrane current activation in response to ACh and caffeine in freshly dissociated arterial endothelial cells. ACh and caffeine evoked transient increases in [Ca2+]i. The initial increase in [Ca2+]i was acco...

Modulation of intracellular calcium ion concentration ((Ca2+)i) could be used to control cellular and molecular responses that are important in cell and tissue engineering. Electrical stimulation (ES) has been used to activate plasma membrane ion channels including Ca2+channels, and to induce changes in (Ca2+)i. Strong direct current (dc) ES depolarizes the membrane electrical potential (MEP) a...