Involvement of sialic acid in high-affinity uptake of dopamine by synaptosomes from rat brain.
The high-affinity, sodium-dependent uptake of dopamine (DA) was inhibited by the pretreatment of synaptosomes with neuraminidase from Vibrio cholerae. The inhibition was of a non-competitive type, resulting in a 40% decrease of Vmax. Neither basal nor depolarization-stimulated release of DA was affected. Treatment of synaptosomes with neuraminidase caused a 48% loss of sialic acid from the lipid-bound pool and a 80% decrease in the protein-bound fraction. The inhibition of DA uptake was found to be related linearly to the loss of sialic acid from the protein pool. It is postulated that a sialic acid moiety is involved in DA transport across the synaptosomal membrane.
Zaleska
M M
MM
Department of Biochemistry and Biophysics, University of Pennsylvania, School of Medicine, Philadelphia 19104.
Erecińska
M
M
D000818:Animals; D004298:Dopamine / Q000493:pharmacokinetics*; D066298:In Vitro Techniques; D008297:Male; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase; D051381:Rats; D011919:Rats, Inbred Strains; D012794:Sialic Acids / Q000378:metabolism / Q000502:physiology*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
D012794:Sialic Acids; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; D004298:Dopamine