Down-regulation of the noradrenaline transporter by interferon-alpha in cultured bovine adrenal medullary cells.
The aim of this study was to investigate the effect of long-term treatment with interferon (IFN)-alpha on the noradrenaline transporter of bovine adrenal medullary cells. Treatment of cultured adrenal medullary cells with IFN-alpha caused a decrease in uptake of [3H]noradrenaline by the cells in time (4-48 h)- and concentration (300-1,000 U/ml)-dependent manners. IFN-beta also inhibited [3H]noradrenaline uptake to a lesser extent than did IFN-alpha, whereas IFN-gamma had little effect. An anti-IFN-alpha antibody reduced the effect of IFN-alpha on [3H]noradrenaline uptake. Saturation analysis of [3H]noradrenaline uptake showed that the inhibitory effect of IFN-alpha was due to a reduction in the maximal uptake velocity (Vmax) values without altering apparent Michaelis constant (Km) values. Incubation of cells with IFN-alpha caused a translocation of protein kinase C from the soluble to the particulate fraction in the cells. The effect of IFN-alpha on [3H]noradrenaline uptake was diminished in protein kinase C-down-regulated cells. Incubation of cells with IFN-alpha for 48 h significantly reduced the specific binding of [3H]desipramine to crude plasma membranes isolated from cells. Scatchard analysis of [3H]desipramine binding revealed that IFN-alpha decreased the maximal binding (Bmax) values without any change in the dissociation constant (K(D)) values. These findings suggest that IFN-alpha suppresses the function of noradrenaline transporter by reducing the density of the transporter in cell membranes through, at least in part, a protein kinase C pathway.
Toyohira
Y
Y
Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan.
Yanagihara
N
N
Minami
K
K
Ueno
S
S
Uezono
Y
Y
Tachikawa
E
E
Kondo
Y
Y
Kashimoto
T
T
Izumi
F
F
D000313:Adrenal Medulla / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology; D000818:Animals; D000906:Antibodies / Q000276:immunology; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003891:Desipramine / Q000378:metabolism; D016898:Interferon-alpha / Q000276:immunology / Q000494:pharmacology*; D007372:Interferons / Q000494:pharmacology; D007700:Kinetics; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000493:pharmacokinetics; D050484:Norepinephrine Plasma Membrane Transport Proteins; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D012016:Reference Values; D027981:Symporters
D018759:Adrenergic Uptake Inhibitors; D000906:Antibodies; D002352:Carrier Proteins; D016898:Interferon-alpha; D050484:Norepinephrine Plasma Membrane Transport Proteins; D027981:Symporters; D007372:Interferons; D011493:Protein Kinase C; D003891:Desipramine; D009638:Norepinephrine