Evidence that synaptosomal high-affinity carriers for amino acid neurotransmitters are glycosylated

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6022412

Zaleska, M M; Erecinska, M

The effect of removal of surface sialic acid from synaptosomes on the high-affinity, Na/sup +/-dependent uptake systems for amino acid neurotransmitters was evaluated. Synaptosomes from rat forebrain were preincubated with neuraminidase from Vibrio cholerae for 20 min at 34/sup 0/. After washing and resuspension, their ability to transport /sup 14/C-GABA and the acidic amino acid, /sup 3/H-aspartate was studied. Pretreatment with neuraminidase resulted in a concentration-dependent inhibition of the uptake of both amino acids while the influx of /sup 3/H-L-leucine was unaffected. Inhibition was a function of the amount of sialic acid released from membranes. The analysis of the kinetic parameters of amino acid uptake revealed that inhibition resulted from a decrease of Vmax without any change in the Km. Neither the synaptosomal energy levels nor the internal concentration of potassium ions was affected by the pretreatment with neuraminidase. The maximum accumulation ratios for both amino acids remained largely unaltered. It is concluded that the GABA and acidic amino acid transporters are glycosylated and that sialic acid is involved in the operation of carrier proteins directly and not through modification of the driving forces responsible for amino acid transport.

• Research Organization: Univ. of Pennsylvania, Philadelphia
• OSTI ID: 6022412
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
AMINO ACIDS
AMINOBUTYRIC ACID
ANIMALS
ASPARTIC ACID
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BODY
BRAIN
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
CHEMISTRY
DRUGS
ENZYMES
GLYCOSYL HYDROLASES
HYDROLASES
INHIBITION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LEUCINE
MAMMALS
MEMBRANE TRANSPORT
METABOLISM
MONOSACCHARIDES
NERVES
NERVOUS SYSTEM
NEUROREGULATORS
O-GLYCOSYL HYDROLASES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RATS
REACTION KINETICS
RODENTS
SACCHARIDES
SIALIC ACID
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES