title: Characterization of the vesicular monoamine transporter in cultured rat sympathetic neurons: persistence upon induction of cholinergic phenotypic traits.
abstract: The binding of [3H]dihydrotetrabenazine ([3H]TBZOH), a specific ligand of the reserpine-sensitive monoamine transporter in brain and adrenal medulla storage vesicles, has been measured in cultured sympathetic neurons from newborn rat in relation to their neurotransmitter phenotype. As shown previously, neurons cultured in the absence of muscle-conditioned medium displayed high activities in catecholamine synthesizing enzymes and low levels of choline acetyltransferase, and neurons cultured in conditioned medium displayed the reverse pattern (J. P. Swerts, A. Le Van Thai, A. Vigny, and M. J. Weber, Dev. Biol. 100, 1-11, 1983). The density of [3H]TBZOH binding sites as well as their subcellular distribution were identical in both types of cultures. Two other structures rich in choline acetyltransferase, the electric organ of Torpedo and the ciliary ganglion of the chick embryo did not contain measurable amounts of [3H]TBZOH binding sites, suggesting that the monoamine transporter is not an ubiquitous component of cholinergic synaptic vesicles. These data suggest that the synthesis of the monoamine transporter in sympathetic neurons is not coregulated with the syntheses of the three norpinephrine synthesizing enzymes. It is proposed that the same population of synaptic vesicles can accumulate acetylcholine or catecholamine, depending only upon which neurotransmitter synthesizing enzymes are expressed by sympathetic neurons.
mesh_terms: D000588:Amines / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism; D002642:Chick Embryo; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D002837:Chromaffin Granules / Q000378:metabolism; D004557:Electric Organ / Q000378:metabolism; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000378:metabolism*; D007700:Kinetics; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D013572:Synaptic Vesicles / Q000378:metabolism; D013747:Tetrabenazine / Q000031:analogs & derivatives / Q000378:metabolism; D014101:Torpedo
chemical_list: D000588:Amines; D002352:Carrier Proteins; C032811:dihydrotetrabenazine; D002795:Choline O-Acetyltransferase; D013747:Tetrabenazine