Subcellular localization of α-2A-adrenergic receptors in the rat medial nucleus tractus solitarius

Regional targeting and relationship with catecholamine neurons

Michael J. Glass, Jie Huang, Sue Aicher, Teresa A. Milner, Virginia M. Pickel

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

α-2A-adrenergic receptor (α2A-AR) agonists modulate diverse autonomic functions. These actions are believed to involve functionally specialized, second-order neurons in catecholamine-containing portions of the medial nucleus tractus solitarius (mNTS) at both intermediate (NTSi) and caudal (NTSc) levels. However, the cellular mechanisms subserving α2A-AR-mediated actions within the mNTS have yet to be established. Immunocytochemistry was employed to examine the subcellular distribution of α2A-AR in both the intermediate and caudal mNTS and its association with cells containing the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH). Quantitative regional comparison using immunogold showed that this receptor was distributed differentially to dendrites (NTSi, 46%; NTSc, 31%) and glia (NTSi, 29%; NTSc, 48%) at different levels of the NTS. Somata, axons, and terminals less frequently contained α2A-AR. The subcellular distribution of α2A-AR relative to catecholaminergic neurons also was similar within both subregions. Approximately 50% of α2A-AR-labeled somata also contained TH. In somatic profiles, α2A-AR labeling was often found in the cytosol and in association with endoplasmic reticulum and Golgi complexes, sites of receptor synthesis and trafficking. Approximately 20% of α2A-AR-immunoreactive dendrites also contained TH, where the receptor was often found on extrasynaptic portions of the plasma membrane near unlabeled terminals, some of which made symmetric contacts. However, TH-labeled terminals and dendrites usually were detected in the neuropil at a short distance (2A-AR-labeled neurons. α2A-AR-labeled glia frequently apposed unlabeled dendrites and terminals and were often located near TH-immunoreactive dendrites. These results indicate that, within the mNTS, α2A-AR is involved in a variety of autonomic processes, including postsynaptic modulation of mostly noncatecholaminergic dendrites, as well as influencing glia functions.

Original languageEnglish (US)
Pages (from-to)193-207
Number of pages15
JournalJournal of Comparative Neurology
Volume433
Issue number2
DOIs
StatePublished - Apr 30 2001
Externally publishedYes

Fingerprint

Solitary Nucleus
Adrenergic Receptors
Catecholamines
Neurons
Dendrites
Tyrosine 3-Monooxygenase
Neuroglia
Carisoprodol
Adrenergic Agonists
Neuropil
Presynaptic Terminals
Golgi Apparatus
Endoplasmic Reticulum
Cytosol
Immunohistochemistry
Cell Membrane

Keywords

  • Autonomic nervous system
  • Clonidine
  • Glia
  • Immunocytochemistry
  • Withdrawal

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Subcellular localization of α-2A-adrenergic receptors in the rat medial nucleus tractus solitarius : Regional targeting and relationship with catecholamine neurons. / Glass, Michael J.; Huang, Jie; Aicher, Sue; Milner, Teresa A.; Pickel, Virginia M.

In: Journal of Comparative Neurology, Vol. 433, No. 2, 30.04.2001, p. 193-207.

Research output: Contribution to journalArticle

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