title: Manganese accumulation in membrane fractions of primary astrocytes is associated with decreased γ-aminobutyric acid (GABA) uptake, and is exacerbated by oleic acid and palmitate.
abstract: Manganese (Mn) exposure interferes with GABA uptake; however, the effects of Mn on GABA transport proteins (GATs) have not been identified. We sought to characterize how Mn impairs GAT function in primary rat astrocytes. Astrocytes exposed to Mn (500 μM) had significantly reduced (3)H-GABA uptake despite no change in membrane or cytosolic GAT3 protein levels. Co-treatment with 100 μM oleic or palmitic acids (both known to be elevated in Mn neurotoxicity), exacerbated the Mn-induced decline in (3)H-GABA uptake. Mn accumulation in the membrane fraction of astrocytes was enhanced with fatty acid administration, and was negatively correlated with (3)H-GABA uptake. Furthermore, control cells exposed to Mn only during the experimental uptake had significantly reduced (3)H-GABA uptake, and the addition of GABA (50 μM) blunted cytosolic Mn accumulation. These data indicate that reduced GAT function in astrocytes is influenced by Mn and fatty acids accumulating at or interacting with the plasma membrane.
authors.affiliation: Department of Nutrition, University of North Carolina at Greensboro, 318 Stone Building, P.O. Box 26170, Greensboro, NC 27402-6170, United States. Electronic address: scfordah@uncg.edu.
authors.forename: Steve C
authors.initials: SC
authors.lastname: Fordahl
authors.affiliation: Department of Nutrition, University of North Carolina at Greensboro, 318 Stone Building, P.O. Box 26170, Greensboro, NC 27402-6170, United States. Electronic address: kmerikso@uncg.edu.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Erikson
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D050485:GABA Plasma Membrane Transport Proteins / Q000378:metabolism; D008345:Manganese / Q000633:toxicity*; D019301:Oleic Acid / Q000494:pharmacology; D010168:Palmitates / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D050485:GABA Plasma Membrane Transport Proteins; D010168:Palmitates; C493417:Slc6a11 protein, rat; D019301:Oleic Acid; D008345:Manganese; D005680:gamma-Aminobutyric Acid; D011493:Protein Kinase C
keywords: Astrocyte; Fatty acid; GABA; Manganese; Neurotoxicity