Flow cytometry-based methods have been developed to measure most neutrophil responses. The assessment of the mobilization of calcium, however, is routinely performed on neutrophils isolated from whole blood. This report describes a flow cytometry-based assay to measure the mobilization of calcium in neutrophils directly in whole blood. This method requires minimal sample manipulation, small vol...

In the U937 histiocytic cell line, we investigated the effect of calcium-mobilizing agents with or without tumor necrosis factor-a (TNF) on the regulation of the synthesis of plasminogen activator inhibitor-type 1 (PAI-l). Cultured U937 cells were stimulated with ionophore A23187 and thapsigargin with or without TNF. The response was analyzed in terms of cytosolic calcium mobilization, PAL1 acc...

27-nor-25-Hydroxyvitamin D3, 26,27-bisnor-25-hydroxyvitamin D3, and 22-27-hexanor-20-hydroxyvitamin D3 and the corresponding 5,6-trans isomers have been synthesized. All compounds were tested for their ability to induce intestinal calcium transport and bone calcium mobilization in normal and anephric rats. The 27-nor- and 26,27-bisnor-25-hydroxyvitamin D3 analog are capable of stimulating intes...

Administration of 60 pmoles of 1,25-dihydroxycholecalciferol to vitamin D-deficient rats on a low calcium diet gives a maximal intestinal calcium transport response in 7 hr and a maximal bone calcium mobilization response in 12 hr. During the 48 hr after injection of radioactive 1,25-dihydroxycholecalciferol, unchanged 1,25-dihydroxycholecalciferol accounts for 71-98% of the radioactivity found...

Signaling through the high affinity receptor for immunoglobulin E (Fc epsilon RI) results in the coordinate activation of tyrosine kinases before calcium mobilization. Receptors capable of interfering with the signaling of antigen receptors, such as Fc epsilon RI, recruit tyrosine and inositol phosphatases that results in diminished calcium mobilization. Here, we show that antibodies recognizin...

We have used RNA interference previously to demonstrate that G protein-coupled receptor kinase 2 (GRK2) regulates endogenously expressed H1 histamine receptor in human embryonic kidney 293 cells. In this report, we investigate the regulation of endogenously expressed M(3) muscarinic acetylcholine receptor (M(3) mAChR). We show that knockdown of GRK2, GRK3, or GRK6, but not GRK5, significantly i...

The 21-amino-acid peptide ET-1 (endothelin-1) regulates a diverse array of physiological processes, including vasoconstriction, angiogenesis, nociception and cell proliferation. Most of the effects of ET-1 are associated with an increase in intracellular calcium concentration. The calcium influx and mobilization pathways activated by ET-1, however, vary immensely. The present review begins with...

Laser-induced vessel wall injury leads to rapid thrombus formation in an animal thrombosis model. The target of laser injury is the endothelium. We monitored calcium mobilization to assess activation of the laser-targeted cells. Infusion of Fluo-4 AM, a calcium-sensitive fluorochrome, into the mouse circulation resulted in dye uptake in the endothelium and circulating hematopoietic cells. Laser...

The development of a vitamin D-resistant state in the course of renal failure may be responsible for reduced intestinal absorption of calcium and an impaired response of skeletal tissue. Moreover, the kidney has been shown to carry out the conversion of 25-hydroxycholecalciferol (25-OH-CC) to a highly biologically active metabolite, 1,25-dihydroxycholecalciferol (1,25-diOH-CC). In the present s...

This study provides new information about the relative importance of calcium mobilization and entry in the renal vascular response to adrenoceptor activation in afferent arterioles isolated from 7- to 8-wk-old Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Intracellular free calcium concentration ([Ca(2+)](i)) was measured in microdissected arterioles utilizing ratiometric photom...