Ultrastructural relations between beta-adrenergic receptors and catecholaminergic neurons

Brain Res Bull. Sep-Oct 1992;29(3-4):257-63. doi: 10.1016/0361-9230(92)90055-3.

Abstract

We performed dual electron microscopic immunocytochemistry to determine the precise cellular relations between beta-adrenergic receptors (beta AR) and catecholaminergic terminals within adult rat brains. An antibody, beta AR404, against a peptide corresponding to the C-terminus of the hamster lung beta AR (beta 2 subtype) together with an anti-tyrosine hydroxylase (TH), a catecholaminergic marker, were used. Results show predominant labeling for beta AR404 within small astrocytic processes (beta-A). This is in sharp contrast to earlier results which showed neuronal labeling when using antibodies against the third intracellular loop of the receptor and of neurons-plus-astrocytes labeled using antibodies against the whole beta AR molecule. beta-A within visual cortex and nuclei of the solitary tracts frequently contacted blood vessel basement membrane and TH-immunoreactive terminals. TH-immunoreactive axons forming axo-axonic juxtapositions with non-TH terminals were also noted to be surrounded by beta-A. In the area postrema, a brain region lacking a blood-brain barrier, few beta-A occurred adjacent to TH-immunoreactive terminals or elsewhere. Thus, 1) catecholamines may act beyond morphologically identifiable synapses; 2) beta-A may mediate interactions between catecholamines and other transmitters; 3) there may be substantial heterogeneity in the structure or the conformation of the beta AR protein between neurons and glia or across CNS regions.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Axons / physiology
  • Catecholamines / physiology*
  • Cricetinae
  • Immunohistochemistry
  • Microscopy, Electron
  • Molecular Sequence Data
  • Neurons / ultrastructure*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, beta / ultrastructure*
  • Visual Cortex / physiology
  • Visual Cortex / ultrastructure

Substances

  • Catecholamines
  • Receptors, Adrenergic, beta