Increases in intraluminal shear stress are thought to cause vasodilation of coronary arterioles by activation of Ca2+-dependent endothelial nitric oxide synthase followed by release of nitric oxide. We tested the hypothesis that endothelium-dependent vasodilation of isolated coronary arterioles to shear stress and agonists is necessarily preceded by an increase in endothelial cell Ca2+concentra...

Relative intracellular free Ca2+ concentrations ([Ca2+]i) were monitored in mature unfertilized mouse eggs by measuring fluorescence of intracellular fluo3. A number of different agents were found to cause sustained repetitive transient [Ca2+1] oscillations. These were microinjection of a cytosolic sperm factor, sustained injection of Ins-(1,4,5)P,, or extracellular addition of the thiol reagen...

To determine features of the steady state [Ca2+]-tension relationship in intact heart, we measured steady force and intracellular [Ca2+] ([Ca2+]i) in tetanized ferret papillary muscles. [Ca2+]i was estimated from the luminescence emitted by muscles that had been microinjected with aequorin, a Ca2+-sensitive, bioluminescent protein. We found that by raising extracellular [Ca2+] and/or by exposin...

PURPOSE To determine if there is endothelin-mediated regulation of cell signaling and proliferation in rabbit corneal epithelium. METHODS Endothelin-1 (ET-1) gene and protein expression by the rabbit corneal epithelial (RCE) cells were analyzed by polymerase chain reaction, sequence analysis, and enzyme immunoassay. DNA synthesis was characterized by [3H]-thymidine uptake. Endothelin receptor...

Hepatic macrophages are sensitized to alcohol in 24 h due to increases in the endotoxin receptor, CD14; however, desensitization to lipopolysaccharide (LPS), which occurred earlier, could not be explained by changes in CD14. Therefore, the purpose of this work was to attempt to understand factors responsible for ethanol-induced desensitization to LPS in hepatic macrophages. Rats were given etha...

The requirements of purified rat Leydig cells for intra- and extra-cellular Ca2+ during steroidogenesis stimulated by LH (lutropin), cyclic AMP analogues and LHRH (luliberin) agonist were investigated. The intracellular Ca2+ concentrations ([Ca2+]i) were measured by using the fluorescent Ca2+ chelator quin-2. The basal [Ca2+]i was found to be 89.4 +/- 16.6 nM (mean +/- S.D., n = 25). LH, 8-brom...

The origin of intracellular Ca2+ concentration ([Ca2+]i) transients stimulated by nicotinic (nAChR) and muscarinic (mAChR) receptor activation was investigated in fura-2-loaded neonatal rat intracardiac neurons. ACh evoked [Ca2+]i increases that were reduced to approximately 60% of control in the presence of either atropine (1 microM) or mecamylamine (3 microM) and to <20% in the presence of bo...

Cerebral palsy is a common birth disorder that frequently involves ischemic-type injury to developing white matter (WM). Dead glial cells are a common feature of this injury and here we describe a novel form of acute ischemic cell death in developing WM astrocytes. Ischemia, modeled by the withdrawal of oxygen and glucose, evoked [Ca2+]i increases and cell death in astrocytes in post-natal day ...

Spacio-temporal changes of intracellular Ca2+ concentrations ([Ca2+]i) are known to play central role in numerous cellular processes such as muscle contraction, gene expression, development, proliferation and apoptosis1. While global increases in [Ca2+]i in vascular smooth muscle cells (VSMCs) elicit contraction2, 3, [Ca2+]i elevation in endothelial cells (ECs) causes vasorelaxation by triggeri...

We characterized ATP-induced changes in intracellular Ca2+ concentration ([Ca2+]i) and membrane current in cultured rat myenteric neurons using ratiometric Ca2+ imaging with fura-2 and the whole cell patch-clamp technique, respectively. Neuronal cells were functionally identified by [Ca2+]i responses to high K+ and nicotine, which occurred only in cells positive for neuron-specific protein gene...