Differential polarization of serotonin transporters in axons versus soma-dendrites: An immunogold electron microscopy study

J. H. Tao-Cheng, Feng Zhou

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

In spite of the conventional belief that neurotransmitter uptake occurs at the synapses, we demonstrated previously that serotonin transporters and the high-affinity uptake of serotonin were not confined to the terminals but rather occurred throughout the axons [Zhou F. C. et al. (1998) Brain Res. 805, 241-254]. In the present study, the detailed distribution of serotonin transporters over various parts of the neuron was illustrated and analysed morphometrically using a pre-embedding immunogold method with a characterized serotonin transporter antibody at the electron microscopic level. Our findings reveal a highly polarized distribution of serotonin transporters between axons and soma-dendrites in two aspects. (1) On the plasma membrane, serotonin transporter-immunogold is extremely low on soma-dendrites and synaptic junctions, but consistently dense along the axons and perisynaptic area. (2) In contrast, serotonin transporter labeling in the cytoplasm is concentrated in soma and dendrites, particularly on the membranes of rough endoplasmic reticulum, Golgi complexes and tubulovesicular structures, but low in the axoplasm. The extensive distribution of serotonin transporter along the axolemma suggests a broad range of uptake sites beyond synaptic junctions, and is consistent with the notion that the major mode of transmission for serotonin neurons is through volume (extrasynaptic) transmission. The highly polarized distribution also indicates that the major serotonin uptake sites are on axons and not on soma-dendrites.

Original languageEnglish
Pages (from-to)821-830
Number of pages10
JournalNeuroscience
Volume94
Issue number3
DOIs
StatePublished - Oct 1999

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Serotonin Plasma Membrane Transport Proteins
Carisoprodol
Dendrites
Axons
Electron Microscopy
Serotonin
Neurons
Membrane Transport Proteins
Rough Endoplasmic Reticulum
Golgi Apparatus
Synapses
Neurotransmitter Agents
Cytoplasm
Cell Membrane
Electrons
Membranes
Antibodies
Brain

Keywords

  • Extrasynaptic transmission
  • Immunocytochemistry
  • Raphe nucleus
  • Specific serotonin reuptake inhibitor
  • Synaptic cleft
  • Volume transmission

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Differential polarization of serotonin transporters in axons versus soma-dendrites : An immunogold electron microscopy study. / Tao-Cheng, J. H.; Zhou, Feng.

In: Neuroscience, Vol. 94, No. 3, 10.1999, p. 821-830.

Research output: Contribution to journalArticle

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