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HEK293 cells expressing the thyrotropin-releasing hormone (TRH) receptor were transfected with cameleon Ca(2+) indicators designed to measure the free Ca(2+) concentration in the cytoplasm, [Ca(2+)](cyt), and the endoplasmic reticulum (ER), [Ca(2+)](er). Basal [Ca(2+)](cyt) was about 50 nm; thyrotropin-releasing hormone (TRH) or other agonists increased(More)
We have recently shown that chronic neurosteroid, 5 alpha 3 alpha, treatment produced down-regulation of the GABA receptor binding and function, and heterologous uncoupling on the GABAA receptor complex in cultured mammalian cortical neurons. In order to explore the underlying mechanism of these observed down-regulation and heterologous uncoupling(More)
In previous studies we have observed that chronic neurosteroid 5 alpha-pregnan-3 alpha-ol-20-one (5 alpha 3 alpha) treatment produced downregulation of the GABAA receptors, heterologous uncoupling, and decreased heterologous efficacy at the GABAA receptor complex in cultured mammalian cortical neurons. In this study, using whole cell recording, we examined(More)
Three independent methods were used to block internalization of the TRH receptor: cells were infected with vaccinia virus encoding a dominant negative dynamin, incubated in hypertonic sucrose, or stably transfected with a receptor lacking the C-terminal tail. Internalization was blocked in all three paradigms as judged by microscopy using a fluorescently(More)
To determine whether the interaction of the TRH receptor with beta-arrestin is necessary for TRH activation of MAPK, cells expressing either intact or truncated, internalization-defective TRH receptors were transfected with a beta-arrestin-green fluorescent protein conjugate. In cells expressing the wild-type pituitary TRH receptor, TRH caused translocation(More)
We have investigated the effects of chronic treatment with the neurosteroid 5 alpha-pregnan-3 alpha-ol-20-one (5 alpha 3 alpha) on the gamma-aminobutyric acid (GABA)A receptor complex in cultured mammalian cortical neurons. Chronic 5 alpha 3 alpha treatment (up to 2 microM, 5 days) did not produce any changes in the morphological appearance or the cell(More)
Endocytosis and recycling of both thyrotropin-releasing hormone (TRH) and its G-protein-coupled receptor were visualized by conventional and confocal fluorescence microscopy in pituitary cells using a rhodamine-labeled TRH analog (Rhod-TRH) and indirect immunofluorescent staining of cells stably transfected with an epitope-tagged TRH receptor (TRHR). The(More)
Although a primary role of the retinal pigment epithelium (RPE) is the phagocytosis of aged outer segment membranes, the RPE may also phagocytize particulates via several specific receptors that are characteristically present on mononuclear phagocytes of bone marrow origin. In recent immunophenotypic studies, CD68 monoclonal antibodies (mAb) have been shown(More)
The thyrotropin-releasing hormone (TRH) receptor was expressed in embryonic fibroblasts from mice lacking the alpha subunits of Gq and G11 (Fq/11 cells) to determine whether G protein coupling is necessary for agonist-dependent receptor internalization. Neither TRH nor agonists acting on endogenous receptors increased intracellular calcium unless the cells(More)
We investigated the contractile effects of both activated and unactivated polymorphonuclear leukocytes (PMNs) on human vascular tissue to characterize the influence of human PMNs on vascular tone. PMNs were added either unactivated or after f-met-leu-phe (fMLP) activation (10(-8) M), into tissue chambers containing human umbilical vein segments under either(More)