Polyamine uptake in cultured cerebellar granule neurons.
In the present study, we have examined the transport of polyamines in cultured cerebellar granule cells. Our results suggest the existence of two different transporters for polyamines in these neurons. Putrescine and spermidine uptake (K ap m = 2.17 and 1.39 microM, respectively), were affected when extracellular sodium was replaced with choline (about 30% inhibition over controls) or sucrose (about 2.5-fold potentiation over controls). By contrast, the substitution of sodium by choline or sucrose did not modify spermine uptake (K ap m = 13.53 microM) in cerebellar granule cells. Accordingly, alteration of membrane potential with ouabain was able to block putrescine (50% inhibition) and spermidine (60% inhibition) uptake but not spermine uptake. These results indicate that putrescine and spermidine transport in cerebellar granule cells is membrane potential dependent, whereas spermine uptake is not modulated by membrane potential.
Dot
Josep
J
Departamento de Bioquímica y Biologia Molecular Instituto de Neurociencias, Edificio M, Universidad Autónoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain. jose.rodriguez@uab.es
Lluch
Mónica
M
Blanco
Isaac
I
Rodríguez-Alvarez
José
J
D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D015317:Biogenic Polyamines / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000378:metabolism; D018698:Glutamic Acid / Q000633:toxicity; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D011700:Putrescine / Q000378:metabolism; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism
D015317:Biogenic Polyamines; D013096:Spermine; D018698:Glutamic Acid; D013095:Spermidine; D011700:Putrescine