Elsevier

Neuroscience

Volume 71, Issue 3, April 1996, Pages 797-832
Neuroscience

Autoradiographic localization of functional muscarinic receptors in the rat superior cervical sympathetic ganglion reveals an extensive distribution over non-synaptic surfaces of neuronal somata, dendrites and nerve endings

https://doi.org/10.1016/0306-4522(95)00478-5Get rights and content

Abstract

Fast synaptic transmission in sympathetic ganglia is mediated by acetylcholine, acting on nicotinic receptors, yet muscarinic receptors are also present and are involved in the production of slow postsynaptic potentials. In order further to elucidate the role of muscarinic receptors in ganglionic transmission their distribution in the rat superior cervical sympathetic ganglion was investigated autoradiographically by use of the tritiated irreversible muscarinic ligand propylbenzilylcholine mustard. It was observed that this agent blocked the carbachol-evoked hydrolysis of inositol phospholipids in the ganglion and that this response to carbachol is itself inhibitable by selective muscarinic antagonists with a potency sequence which indicates involvement primarily of M1 receptors. Light microscope autoradiography showed that labelling inhibitable by atropine and by the M1-selective muscarinic antagonist pirenzepine was essentially confined to the margins of neuronal somata and regions of dendritic arborization, which include synaptic contacts. Quantitative electron microscope autoradiography showed that binding of the radioligand, of which approximately 70% was inhibitable by atropine and 68% by pirenzepine, was associated predominantly with surface membranes of neuronal somata, dendrites, other neurites (including axons and uncharacterized dendrites) and nerve terminal profiles, in the approximate ratios 95:85:52:45. Of the inhibitable binding over neuronal membranes in the ganglion little more than 3% was found to be synaptically located, and this involved para- or peri-synaptic regions of nerve terminal contacts rather than the specialized synaptic zone. About 5% of the inhibitable binding over neuronal membranes involved non-synaptic surfaces of nerve terminals and preterminal axon segments; almost 70% was distributed over non-synaptic surfaces of neuronal somata and dendrites, and about 21 % upon other neurites. Binding sites were found not to be more highly concentrated at or adjacent to synapses than over other regions of neuronal surface membranes. About 50%, possibly more, of the binding on non-synaptic surfaces of nerve endings, and about 7% of binding upon dendritic membranes, was of non-M1, possibly M2 type, inhibitable by atropine but not by pirenzepine. Non-synaptic neuro-neuronal appositions, which involve dendrites and somata and often lie adjacent to synapses, showed rather more than twice the binding expected for each membrane individually; and neuronal membrane exposed to basal lamina lining ganglionic tissue spaces showed high levels of binding. Little inhibitable binding was seen over membranes of satellite and Schwann cells, or over cytoplasmic territories or ganglionic interstitial tissue. A model was constructed of the distribution of label, which showed that the observed results for total binding could be approximately matched by assuming the following relative densities of ligand binding sites: interstitial tissue space and supporting cells 1, soma cytoplasm 3, cytoplasm of dendrites, neurites and nerve terminals 4.5, surfaces of mesodermal elements 15, surfaces of neurites and nerve endings including sites of synapse 45, surfaces of dendrites 90, surfaces of neuronal somata 120, non-synaptic neuro-neuronal appositions 180.

It is concluded that functional muscarinic receptors in this sympathetic ganglion, predominantly of the M1 type linked with slow depolarizations, but including some non-M, receptors, are widely distributed over non-synaptic surfaces of the neuronal somata and dendrites and are not concentrated at synapses. Presynaptic autoreceptors are also present, of which half or more are of non-Ma possibly M2, type which might be inhibitory. The presence of M4 receptors is not excluded. The observed distribution suggests that muscarinic receptors in the ganglion are appropriately located to be capable of exploiting acetylcholine spilling over from sites of release from preganglionic nerve endings, for which there is evidence in vivo, thereby assisting the co-ordination or reciprocal regulation of recruitment and activity in ganglionic neuronal populations with similar and, or, with opposing functions.

References (95)

  • Y. Kawai et al.

    Correlation between dendrodendritic synapses of adrenergic type and synaptically evoked hyperpolarization in sympathetic ganglia of adult rats

    Neuroscience

    (1995)
  • M. Kiraly et al.

    Neuroneuronal interconnections in the rat superior cervical ganglion; possible anatomical bases for modulatory interactions revealed by intracellular horseradish peroxidase labelling

    Neuroscience

    (1989)
  • L.M. Koval et al.

    Distribution of muscarinic receptors in mammalian sympathetic ganglion: autoradiographic and electrophysiological studies

    J. auton. nerv. Syst.

    (1982)
  • T. Kubo et al.

    Primary structure of porcine cardiac muscarinic acetylcholine receptor deduced from the cDNA sequence

    Fedn Eur. biochem. Socs Len.

    (1986)
  • P.A. Lapchak et al.

    Binding sites for [3H]AF-DX 116 and effect of AF-DX 116 on endogenous acetylcholine release from rat brain slices

    Brain Res.

    (1989)
  • C.-F. Liao et al.

    Molecular cloning and expression of a fifth muscarinic acetylcholine receptor

    J. biol. Chem.

    (1989)
  • R.H. Loring et al.

    The ultrastructural distribution of putative nicotinic receptors on cultured neurons from the rat superior cervical ganglion

    Neuroscience

    (1988)
  • M. Marchi et al.

    Pirenzepine-insensitive muscarinic autoreceptors regulate acetylcholine release in human neocortex

    Brain Res.

    (1990)
  • S. Mochida et al.

    A novel muscarinic receptor antagonist AFDX-116 differentially blocks slow inhibitory and slow excitatory post-synaptic potentials in the rabbit sympathetic ganglia

    Life Sci.

    (1988)
  • N. Newberry

    M1 and M2, receptors mediate different effects on synaptically evoked potentials of the rat superior cervical ganglion

    Neurosci. Lett.

    (1988)
  • Z. Nusser et al.

    Subsynaptic segregation of metabotropic and ionotropic glutamate receptors as revealed by immunogold localization

    Neuroscience

    (1994)
  • D.A. Ramsay et al.

    Denervation-induced formation of adrenergic synapses in the superior cervical sympathetic ganglion of the rat and the enhancement of this effect by postganglionic axotomy

    Neuroscience

    (1985)
  • D.W.Y. Sah et al.

    Long term blockade by toxin F of nicotinic synaptic potentials in cultured sympathetic neurones

    Neuroscience

    (1987)
  • A.N.M. Schoffelmeer et al.

    Muscarine receptor-mediated modulation of [3H]dopamine and [14C]acetylcholine release from rat neostriatal slices: selective antagonism by gallamine but not pirenzepine

    Eur. J. Pharmac.

    (1986)
  • T. Suzuki et al.

    Presynaptic M1 muscarinic receptor modulates spontaneous release of acetylcholine from rat basal forebrain slices

    Neurosci. Lett.

    (1988)
  • S.P. Watson et al.

    Substance P induced hydrolysis of inositol phospholipids in guinea-pig ileum and rat hypothalamus

    Eur. J. Pharmac.

    (1983)
  • F.F. Weight et al.

    Acetylcholine and slow synaptic inhibition in frog sympathetic ganglion cells

    Brain Res.

    (1973)
  • Z.F. Zaidi et al.

    Observations on stimulant-induced exocytosis from neurones in sympathetic ganglia

    J. auton. nerv. Syst.

    (1991)
  • P.R. Adams et al.

    Synaptic inhibition of the M-current: slow excitatory postsynaptic potential mechanism in bullfrog sympathetic neurones

    J. Physiol., Lond.

    (1982)
  • M. Bachoo et al.

    An AF-DX 116 sensitive inhibitory mechanism modulates nicotinic and muscarinic transmission in cat superior cervical ganglion in the presence of anticholinesterase

    Can. J. Physiol. Pharmac.

    (1992)
  • L. Bernheim et al.

    Characterization of muscarinic receptor subtypes inhibiting Ca2+ current and M2 current in rat sympathetic neurons

  • M. Birnbaumer et al.

    Molecular cloning of the receptor for human antidiuretic hormone

    Nature

    (1992)
  • T. Blackett et al.

    A simplified method of “hypothetical grain” analysis of electron microscopic autoradiographs

    J. Histochem. Cytochem.

    (1977)
  • T.I. Bonner et al.

    Identification of a family of muscarinic acetylcholine receptor genes

    Science

    (1987)
  • D.A. Brown et al.

    Muscarinic suppression of a novel voltage-sensitive potassium current in a vertebrate neurone

    Nature

    (1980)
  • D.A. Brown et al.

    Muscarinic receptors in rat sympathetic ganglia

    Br. J. Pharmac.

    (1980)
  • D.A. Brown et al.

    On the transduction mechanism for muscarine-induced inhibition of M-current in cultured sympathetic neurones

    J. Physiol., Lond.

    (1989)
  • D.A. Brown et al.

    Membrane currents underlying the cholinergic slow excitatory post-synaptic potential in the rat sympathetic ganglion

    J. Physiol., Lond.

    (1985)
  • A.S.V. Burgen et al.

    The binding of [3H]-propylbenzilylcholine mustard by longitudinal muscle strips from guinea-pig small intestine

    Br. J. Pharmac.

    (1974)
  • F. de Castro

    Sympathetic ganglia, normal and pathological

  • A.E. Cole et al.

    Muscarinic inhibitory transmission in mammalian sympathetic ganglia mediated by increased potassium conductance

    Nature

    (1984)
  • F. Dauphin et al.

    Cholinergic dilatation and constriction of feline cerebral blood vessels are mediated by stimulation of phosphoinositide metabolism via two different muscarinic receptor subtypes

    J. Neurochem.

    (1994)
  • R. Davis et al.

    Electron microscopic localization of acetylcholinesterase and butyrylcholinesterase in the superior cervical ganglion of the cat. I. Normal ganglion

    J. Cell Biol.

    (1978)
  • R.A.F. Dixon et al.

    Cloning the gene and cDNA for mammalian beta-adrenergic receptor and homology with rhodopsin

    Nature

    (1986)
  • F. Dörje et al.

    Immunological detection of muscarinic receptor subtype proteins (m1–m5) in rabbit peripheral tissues

    Molec. Pharmac.

    (1991)
  • R.M. Eccles

    Responses of isolated curarized sympathetic ganglia

    J. Physiol., Lond.

    (1952)
  • R.M. Eccles et al.

    Origin and blockade of the synaptic responses of curarized sympathetic ganglia

    J. Physiol., Lond.

    (1961)
  • Cited by (13)

    • Presynaptic nicotinic ACh receptors

      1997, Trends in Neurosciences
    View all citing articles on Scopus
    View full text