Glutamate-immunoreactive terminals synapse on primate spinothalamic tract cells

K. N. Westlund, S. M. Carlton, D. Zhang, W. D. Willis

    Research output: Contribution to journalArticle

    35 Citations (Scopus)

    Abstract

    Glutamate has been shown to excite spinothalamic tract (STT) neurons and has been localized to primary afferent neurons, spinal cord projection neurons, and interneurons in the spinal cord dorsal horn. The likelihood that glutamate-immunoreactive (GLU-IR) terminals directly innervate STT neurons was investigated. For these studies three lamina IV or V STT cells in the lumbar spinal cords of three monkeys (Macaca fascicularis) were identified electrophysiologically and characterized. Two were identified as high threshold neurons and one as a wide dynamic range neuron. Following intracellular injection of the cells with HRP and reaction to give the cells a Golgi-like appearance, the tissues were processed for electron microscopy. Postembedding immunogold methods with antibodies specific for glutamate were used to identify GLU-IR terminals apposing the somata and dendrites of the STT neurons, including dendrites that extended into laminae IV and III. The GLU-IR terminals were numerous and constituted a mean of 46% of the population counted that appose the STT soma and 50% of the profiles apposing the dendrites. Fifty-four percent of the somatic and 50% of the dendritic surface length was contacted by GLU-IR terminals. Most terminals contained round clear vesicles and some contained a variable number of large dense core vesicles. For one of the three cells examined it was determined that 45% of the terminals apposing the soma were GLU-IR and 30% of the terminals were gamma aminobutyric acid-immunoreactive (GABA-IR). In an additional monkey, a lamina I cell retrogradely labeled from the ventral posterolateral nucleus of the thalamus was found to be ensheathed in glial processes. Of the 9 terminals observed apposing the retrogradely filled STT neuron in one plane of section, 2 were GLU-IR and 3 were GABA-IR. The data suggest that a large percentage of the profiles adjacent to STT neurons in intermediate laminae of the spinal cord contain glutamate and many synapse directly with STT neurons.

    Original languageEnglish (US)
    Pages (from-to)519-527
    Number of pages9
    JournalJournal of Comparative Neurology
    Volume322
    Issue number4
    StatePublished - 1992

    Fingerprint

    Spinothalamic Tracts
    Synapses
    Primates
    Glutamic Acid
    Neurons
    Spinal Cord
    Carisoprodol
    Dendrites
    Ventral Thalamic Nuclei
    gamma-Aminobutyric Acid
    Haplorhini
    Afferent Neurons
    Macaca fascicularis
    Secretory Vesicles
    Interneurons
    Neuroglia
    Electron Microscopy
    Spinal Cord Dorsal Horn

    Keywords

    • colloidal gold
    • excitatory amino acid
    • gamma-aminobutyric acid
    • monkey
    • pain
    • spinal cord
    • ultrastructure

    ASJC Scopus subject areas

    • Neuroscience(all)

    Cite this

    Westlund, K. N., Carlton, S. M., Zhang, D., & Willis, W. D. (1992). Glutamate-immunoreactive terminals synapse on primate spinothalamic tract cells. Journal of Comparative Neurology, 322(4), 519-527.

    Glutamate-immunoreactive terminals synapse on primate spinothalamic tract cells. / Westlund, K. N.; Carlton, S. M.; Zhang, D.; Willis, W. D.

    In: Journal of Comparative Neurology, Vol. 322, No. 4, 1992, p. 519-527.

    Research output: Contribution to journalArticle

    Westlund, KN, Carlton, SM, Zhang, D & Willis, WD 1992, 'Glutamate-immunoreactive terminals synapse on primate spinothalamic tract cells', Journal of Comparative Neurology, vol. 322, no. 4, pp. 519-527.
    Westlund, K. N. ; Carlton, S. M. ; Zhang, D. ; Willis, W. D. / Glutamate-immunoreactive terminals synapse on primate spinothalamic tract cells. In: Journal of Comparative Neurology. 1992 ; Vol. 322, No. 4. pp. 519-527.
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