Inhibitory effect of xylamine on the uptake of [3H]norepinephrine into primary astrocyte cultures.
Primary astrocyte cultures from neonatal rat brains show a Na+-dependent, desipramine-sensitive uptake of [3H]norepinephrine ([3H]NE). Xylamine, a nitrogen mustard, attenuated this uptake of [3H]NE into the astrocytes (IC50 = 0.8 microM). The dose-dependent reduction of [3H]NE uptake by xylamine indicated competitive kinetics. However, xylamine lost the effect if the active transport inhibitor, ouabain or iodoacetate, was also incubated during the pretreatment period of if Na+ was absent. The activity of Na(+)-K(+)-ATPase in astrocytes was not modified by xylamine at the concentrations sufficient to block the uptake of [3H]NE. These findings suggest that xylamine has the ability to compete with the transport of [3H]NE into astrocytes through an effect on the carrier instead of an action on enzymatic activity.
Chang
T K
TK
Department of Neurology, China Medical College, Taichung City, Taiwan.
Cheng
J T
JT
D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D002478:Cells, Cultured; D003891:Desipramine / Q000494:pharmacology; D007461:Iodoacetates / Q000494:pharmacology; D019807:Iodoacetic Acid; D007700:Kinetics; D009588:Nitrogen Mustard Compounds / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D014316:Tritium
D007461:Iodoacetates; D009588:Nitrogen Mustard Compounds; D014316:Tritium; D010042:Ouabain; C026131:xylamine; D003891:Desipramine; D019807:Iodoacetic Acid; D009638:Norepinephrine