Binding of ligands to N-formyl peptide chemoattractant receptors exposed on human neutrophils generates signals in the cells that induce an activation of the superoxide anion producing NADPH-oxidase. Ligand binding is followed by a rapid association of the ligand-receptor complex with the cytoskeleton, a process leading to desensitization of the cells with respect to NADPH-oxidase activation. W...

Annexin 7 deficiency has previously been shown to foster suicidal death of erythrocytes or eryptosis, which is triggered by increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) and characterized by cell shrinkage and cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface. Eryptosis following increase of [Ca(2+)](i) by Ca(2+) ionophore ionomycin, osmotic...

Dopaminergic (DAergic) neurons possess D2-like somatodendritic and terminal autoreceptors that modulate cellular excitability and dopamine (DA) release. The cellular and molecular processes underlying the rapid presynaptic inhibition of DA release by D2 receptors remain unclear. Using a culture system in which isolated DAergic neurons establish self-innervating synapses ("autapses") that releas...

Carbon monoxide (CO) is produced from heme by heme oxygenase-2 (HO-2) in cerebral blood vessels. Gas chromatography-mass spectrometry was used on piglet cerebral microvessels to address the hypothesis that CO production is regulated by heme delivery and HO-2 catalytic activity. CO production appears to be substrate limited because heme and its precursor aminolevulinate increase CO production. I...

We have investigated the cellular mechanisms by which changes in intracellular calcium (Ca2+) can differentially regulate gene expression. Two Ca2+ paradigms, involving prolonged and transient Ca2+ increases, were used. As a starting point, we studied the slow, prolonged elevation of Ca2+ caused by activation of 5-HT1 receptors. We had previously shown that 5-HT1 agonists inhibit calcitonin gen...

The waltzing guinea pig, possessing an hereditary progressive deafness, shows pathology to the actin-bearing structures within the hair cells of the organ of Corti. In particular, the affected structures include the stereocilia, the cuticular plate and, as shown in the present study, swollen and disorganized subsurface cisternae. To test whether this pathology affected outer hair cell motility,...

Objective: Elite Controllers or Suppressors (ES) are patients who control HIV replication without antiretroviral therapy. In this study, we compared baseline and inducible HIV-1 mRNA levels in CD4+ T cells from ES and chronic progressors (CPs) receiving suppressive antiretroviral therapy. Methods: We quantified basal levels of cell associated HIV-1 mRNA in CD4+ T cells isolated from CPs and ES....

The roles of multifunctional CD4 T cells in human tuberculosis are not well defined. In this study, we found that patients with tuberculosis had decreased PMA/ionomycin stimulated multifunctional CD4 T cells, and increased Mycobacterium tuberculosis antigen-specific multifunctional CD4 T cells, when compared to individuals with latent tuberculosis infection and healthy controls. PMA/ionomycin s...

In rat myometrium labeled with [3H]myristic acid, endothelin (ET)-1 via ET(A) receptors stimulated, in the presence of 0.3% butanol, the formation of [3H]phosphatidylbutanol ([3H]PBut) as a result of phospholipase D activity. Fluoroaluminates increased [3H]PBut generation, which indicated that a heterotrimeric G protein was involved. The ET-1 effect was insensitive to pertussis toxin and was ra...

Gamma-aminobutyric acid (GABA)-containing interneurons of the ventral tegmental area (VTA) regulate the activity of dopaminergic neurons. These GABAergic interneurons are known to be innervated by synaptic terminals containing enkephalin, an endogenous ligand of mu-opioid receptors. Bath application of mu-opioid receptor agonists inhibits the activity of VTA GABAergic neurons but the mechanism ...