Choline Uptake in Nerve Cultures and in Synaptosomal Preparation is Regulated by the Endogenous Pool of Choline

Massarelli, R.; Wong, T.Y.

doi:10.1007/978-1-4684-8643-8_51

Cited by 9 publications

(9 citation statements)

References 11 publications

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“…When synaptosomes (50,63,75) or preparations of chick ciliary muscle (62) were incubated in the presence of 0.5 to 5.0 puM labeled choline, a major fraction of the transported label could be recovered as ACh. In neuronal cultures (72,76) and in photoreceptor cells (74), the choline label is recovered predominantly as PCh and phospholipids, and not as ACh. The association between choline's transport and its acetylation observed in some preparations has been interpreted as reflecting direct (77) or kinetic (62,78) coupling; other observers, noting that the ACh synthesized intrasynaptosomally derives primarily from a preexisting choline pool (79) and that ACh synthesis can be inhibited without affecting choline transport, have concluded that high-affinity choline uptake need not be a selective source for the ACh precursor (80) and that choline's uptake is independent of its acetylation.…”

Section: Factors Supplying Choline To the Brain Neuronsmentioning

confidence: 95%

“…Such transactivation can be explained by a mechanism in which attachment of its ligand to the carrier molecule facilitates the carrier's passage across the membrane. Indeed, the higher the extrasynaptosomal concentration of choline, the greater the efflux of synaptosomal choline into the medium (76,81). Preparations of choline carrier incorporated into liposomes also exhibit transactivation (82).…”

Section: Factors Supplying Choline To the Brain Neuronsmentioning

confidence: 98%

“…Similarly, intracellular choline concentrations must be considered: not all of the synaptosomes prepared from mammalian brain are cholinergic, so that 1.5 nmole of choline per milligram of protein may be an over-or underestimation of the real choline concentration in cholinergic synaptosomes. Loading synaptosomes with exogenous choline stimulates their choline influx (76,81). Such transactivation can be explained by a mechanism in which attachment of its ligand to the carrier molecule facilitates the carrier's passage across the membrane.…”

Section: Factors Supplying Choline To the Brain Neuronsmentioning

confidence: 99%

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Choline and Cholinergic Neurons

Blusztajn

Wurtman

1983

Science

415

151

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Mammalian neurons can synthesize choline by methylating phosphatidylethanolamine and hydrolyzing the resulting phosphatidylcholine. This process is stimulated by catecholamines. The phosphatidylethanolamine is synthesized in part from phosphatidylserine; hence the amino acids methionine (acting after conversion to S-adenosylmethionine) and serine can be the ultimate precursors of choline. Brain choline concentrations are generally higher than plasma concentrations, but depend on plasma concentrations because of the kinetic characteristics of the blood-brain-barrier transport system. When cholinergic neurons are activated, acetylcholine release can be enhanced by treatments that increase plasma choline (for example, consumption of certain foods).

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Section: Factors Supplying Choline To the Brain Neuronsmentioning

confidence: 95%

Section: Factors Supplying Choline To the Brain Neuronsmentioning

confidence: 98%

Section: Factors Supplying Choline To the Brain Neuronsmentioning

confidence: 99%

See 1 more Smart Citation

Choline and Cholinergic Neurons

Blusztajn

Wurtman

1983

Science

415

151

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“…As enumerated by Richardson et al (1989), the principle watersoluble compound into which labeled Cho is incorporated is PCho, as shown with NS-20 neuroblastoma cells (Lanks et al, 1974); neuroblastoma X glioma hybrid cells, NG108-15 (Blusztajn et al, 1986); dissociated neurons of chick brain and rat brain synaptosomes (Massarelli and Wong, 1981;Wong et al, 1983); and cultures of septal slices of neonatal rats (Keller et al, 1987) in vivo, which may be a possible precursor for AcCho synthesis.…”

Section: Discussionmentioning

confidence: 99%

The metabolic fate of [3H-methyl]choline in cultured human neuroblastoma cell lines, LA-N-1 and LA-N-2

Singh

Sorrentino

Massarelli³

et al. 1991

Molecular and Chemical Neuropathology

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The conversion of choline in cultures of the human neuroblastoma cell lines, LA-N-1 and LA-N-2 cells, was investigated in order to identify potential precursors in acetylcholine (AcCho) synthesis. LA-N-1, a catecholaminergic and LA-N-2, a cholinergic, cell line were incubated with [ 3 H-methyl]choline (Cho) for varying periods of time up to 72 h. The radioactivity present in lipids and watersoluble metabolites increased linearly up to 24 h in both cell lines. Approximately 20% of the radioactivity associated with the watersoluble metabolites in both control (untreated) and retinoic acidinduced differentiated (RA-treated cells) LA-N-2 cells was present as Cho and AcCho. There was no detectable AcCho in the catecholaminergic cell line, LA-N-1.The untreated and RA-treated LA-N-1 and LA-N-2 cells were labeled for 24 h with [ 3H-methyl]Cho, followed by a chase in growth medium containing 100 µM unlabeled choline. The distribution of radioactivity in the LA-N-2 cells was 6-10% of AcCho, 84-89% as phosphocholine (PCho), 1-3% as glycerophosphocholine (GroPCho),

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“…Since Massarelli and Wong (1981) suggested that CK activity may be coupled to the transport of choline in neuronal membranes, we investigated the subcellular distribution of CK activity in rat striatum (Reinhardt and Wecker, 1983).…”

Section: Choline Kinasementioning

confidence: 99%