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Zinc-enriched GABAergic terminals in mouse spinal cord.
Brain Res. 2001 Dec 07; 921(1-2):165-72.BR

Abstract

Electrophysiological experiments have shown that zinc ions modulate glutamate and GABA receptors in brain slices. All the zinc-enriched neuronal pathways in the brain analyzed up until now have been found to be glutaminergic. Many years ago, zinc-enriched terminals with flat vesicles and symmetric synapses were found to be present in rat spinal cord by Henrik Daa Schrøder, and recently these findings have been supported by immunohistochemical and electron microscopical data in lamprey, mouse and rat. In the present study we expanded these observations by revealing a colocalization of zinc ions, zinc transporter-3 (ZnT3) and glutamic acid decarboxylase (GAD) in synaptic vesicles of zinc-enriched terminals throughout the mouse spinal cord. Confocal analysis of ZnT3 and GAD immunofluorescence was used at light microscopical levels, and a combination of zinc selenium autometallography and GAD immunocytochemistry at electron microscopic levels. Zinc-enriched/GABAergic terminals were observed in all laminae of the spinal gray matter, but most densely populated were laminae I and III in the dorsal horn. In the lateral and ventral funiculi of the white matter, rows of inhibitory zinc-enriched boutons were seen radiating from the gray matter. Ultrastructurally, colocalization of zinc ions and GAD immunoreactivity was seen in a pool of presynaptic terminals in the above locations. Some zinc-enriched terminals were not GAD-positive and some GAD-positive terminals were void of zinc ions. The majority of the zinc-enriched, not GABAergic terminals could be classified as excitatory based on their morphology, i.e. round clear vesicles and symmetric synapses. We conclude that a majority of the spinal cord zinc-enriched terminals are GABAergic. The zinc-enriched terminals with excitatory morphology are most likely glutaminergic, a few have an inhibitory morphology but are not GABAergic. These are most likely glycinergic.

Authors+Show Affiliations

Department of Anatomy and Cell Biology, Göteborg University, Gothenburg, Sweden.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11720723

Citation

Wang, Z, et al. "Zinc-enriched GABAergic Terminals in Mouse Spinal Cord." Brain Research, vol. 921, no. 1-2, 2001, pp. 165-72.
Wang Z, Li JY, Dahlström A, et al. Zinc-enriched GABAergic terminals in mouse spinal cord. Brain Res. 2001;921(1-2):165-72.
Wang, Z., Li, J. Y., Dahlström, A., & Danscher, G. (2001). Zinc-enriched GABAergic terminals in mouse spinal cord. Brain Research, 921(1-2), 165-72.
Wang Z, et al. Zinc-enriched GABAergic Terminals in Mouse Spinal Cord. Brain Res. 2001 Dec 7;921(1-2):165-72. PubMed PMID: 11720723.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Zinc-enriched GABAergic terminals in mouse spinal cord. AU - Wang,Z, AU - Li,J Y, AU - Dahlström,A, AU - Danscher,G, PY - 2001/11/27/pubmed PY - 2002/2/9/medline PY - 2001/11/27/entrez SP - 165 EP - 72 JF - Brain research JO - Brain Res. VL - 921 IS - 1-2 N2 - Electrophysiological experiments have shown that zinc ions modulate glutamate and GABA receptors in brain slices. All the zinc-enriched neuronal pathways in the brain analyzed up until now have been found to be glutaminergic. Many years ago, zinc-enriched terminals with flat vesicles and symmetric synapses were found to be present in rat spinal cord by Henrik Daa Schrøder, and recently these findings have been supported by immunohistochemical and electron microscopical data in lamprey, mouse and rat. In the present study we expanded these observations by revealing a colocalization of zinc ions, zinc transporter-3 (ZnT3) and glutamic acid decarboxylase (GAD) in synaptic vesicles of zinc-enriched terminals throughout the mouse spinal cord. Confocal analysis of ZnT3 and GAD immunofluorescence was used at light microscopical levels, and a combination of zinc selenium autometallography and GAD immunocytochemistry at electron microscopic levels. Zinc-enriched/GABAergic terminals were observed in all laminae of the spinal gray matter, but most densely populated were laminae I and III in the dorsal horn. In the lateral and ventral funiculi of the white matter, rows of inhibitory zinc-enriched boutons were seen radiating from the gray matter. Ultrastructurally, colocalization of zinc ions and GAD immunoreactivity was seen in a pool of presynaptic terminals in the above locations. Some zinc-enriched terminals were not GAD-positive and some GAD-positive terminals were void of zinc ions. The majority of the zinc-enriched, not GABAergic terminals could be classified as excitatory based on their morphology, i.e. round clear vesicles and symmetric synapses. We conclude that a majority of the spinal cord zinc-enriched terminals are GABAergic. The zinc-enriched terminals with excitatory morphology are most likely glutaminergic, a few have an inhibitory morphology but are not GABAergic. These are most likely glycinergic. SN - 0006-8993 UR - https://www.unboundmedicine.com/medline/citation/11720723/Zinc_enriched_GABAergic_terminals_in_mouse_spinal_cord_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0006-8993(01)03114-6 DB - PRIME DP - Unbound Medicine ER -