Manganese Uptake and Efflux in Cultured Rat Astrocytes

• DOI: 10.1111/j.1471-4159.1992.tb09778.x
• Publication Date: 2006-10-06T02:33:24Z
• Authors: Michael Aschner; Maureen Gannon; Harold K. Kimelberg
• Keywords: Efflux; Divalent

Abstract: Astrocytes play a central role in manganese (Mn) regulation the CNS. Using primary astrocyte cultures from neonatal rat brains, these studies demonstrate specific highaffinity transport system for Mn 2+ . Saturation kinetics are clearly indicated by both l/ s versus plots ( K m = 0.30 ± 0.03 μMM; V max 0.02 nmol/mg of protein/min) and v [ ]. Several divalent cations (Co 2 , Zn Pb ) failed to inhibit initial rate 54 uptake. In contrast, extracellular Ca at 10 μM decreased Exchange with was not obligatory efflux into medium because occurred ‐free medium, but enhanced when astrocytes were equilibrated presence unlabeled Efflux biphasic rapid slow component. most during first min incubation, 27.5 2.2% transported extracellularly, 37.2 1.2% preloaded retained 120 min. These show, time, that mammalian can via system.