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Scientific article
English

Magnocellular neurons of the rat supraoptic nucleus are endowed with functional nicotinic acetylcholine receptors

Contributors

Zaninetti, M.; Blanchet, Christophe; Tribollet, Eliane; Bertrand, Daniel; Raggenbass, Mario

Published in

Neuroscience, vol. 95, no. 2, p. 319-323

Publication date

1999

Abstract

Acetylcholine can stimulate the release of vasopressin. In organ-cultured hypothalamo-neurohypophyseal systems, acetylcholine enhanced vasopressin release by acting in or near the supraoptic nucleus Extracellular recordings suggested that acetylcholine can increase supraoptic neuron excitability. These effects could be mimicked, in part, by nicotine or blocked by nicotinic antagonists, suggesting that they might be mediated by nicotinic acetylcholine receptors. Autoradiography indicated that alpha-bungarotoxin binding sites are present in the supraoptic nucleus; however, neither acetylcholine nor nicotine binding sites could be detected. Thus, the existence, let alone the nature, of nicotinic receptors in the supraoptic nucleus has so far remained elusive. The present work attempts to determine: (i) whether functional nicotinic receptors are present in this nucleus; (ii) whether they are located on neurosecretory magnocellular cells or at presynaptic sites; (iii) what their pharmacological and biophysical properties are; (iv) whether they influence the activity of all or only part of supraoptic neurons. Whole-cell recordings were performed in hypothalamic slices or in acutely dissociated supraoptic neurons and the effect of nicotinic agonists was tested under voltage-clamp conditions. Autoradiography was done in coronal hypothalamic sections, using [3H]epibatidine and [125I]alpha-bungarotoxin as ligands. Our results indicate that supraoptic neurons possess functional nicotinic receptors containing the alpha7 subunit.

Keywords

  • Acetylcholine/pharmacology
  • Animals
  • Bicyclo Compounds, Heterocyclic/metabolism/pharmacology
  • Bungarotoxins/metabolism/pharmacology
  • Dihydro-beta-Erythroidine/pharmacology
  • Dose-Response Relationship, Drug
  • Electrophysiology
  • Iodine Radioisotopes/diagnostic use
  • Male
  • Membrane Potentials/drug effects/physiology
  • Neurons/ chemistry/ physiology
  • Nicotine/pharmacology
  • Nicotinic Agonists/pharmacology
  • Nicotinic Antagonists/pharmacology
  • Pyridines/metabolism/pharmacology
  • Radioligand Assay
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Nicotinic/ physiology
  • Supraoptic Nucleus/ cytology
  • Tritium/diagnostic use
  • Vasodilator Agents/pharmacology

UNIGE affiliation entities

Citation (ISO format)

ZANINETTI, M. et al. Magnocellular neurons of the rat supraoptic nucleus are endowed with functional nicotinic acetylcholine receptors. In: Neuroscience, 1999, vol. 95, n° 2, p. 319–323. doi: 10.1016/s0306-4522(99)00477-7

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Article

Identifiers

Journal ISSN

0306-4522
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Creation

06/08/2010 13:48:14

First validation

06/08/2010 13:48:14

Update

14/03/2023 15:59:49

Status update

14/03/2023 15:59:49

Last indexation

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