Nicotine suppression of gustatory responses of neurons in the nucleus of the solitary tract

J Neurophysiol. 2006 Oct;96(4):1877-86. doi: 10.1152/jn.00345.2006. Epub 2006 Jul 12.


This study investigated effects of nicotine applied to the tongue surface on responses of gustatory neurons in the nucleus of the solitary tract (NTS) in rats. In pentobarbital-anesthetized rats, single-unit recordings were made from NTS units responsive to one or more tastants (sucrose, NaCl, citric acid, monosodium glutamate, quinine). Application of nicotine (0.87, 8.7, or 600 mM) excited gustatory NTS units and significantly attenuated NTS unit responses to their preferred tastant in a dose-dependent manner. The depressant effect of nicotine was equivalent regardless of which tastant best excited the NTS unit. Nicotinic excitation of NTS units and depression of their tastant-evoked responses were both significantly attenuated by the nicotinic antagonist mecamylamine, which itself did not excite NTS units. In rats with bilateral trigeminal ganglionectomy, nicotine still excited nearly all NTS units but no longer depressed tastant-evoked responses. Nicotine did not elicit plasma extravasation when applied to the tongue. The results indicate that nicotine directly excites NTS units by gustatory nerves and inhibits their tastant-evoked responses by a nicotinic acetylcholine receptor-mediated excitation of trigeminal afferents that inhibit NTS units centrally.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Capsaicin / pharmacology
  • Dose-Response Relationship, Drug
  • Ganglia, Sensory / drug effects
  • Ganglia, Sensory / physiology
  • Ganglionic Stimulants / antagonists & inhibitors
  • Ganglionic Stimulants / pharmacology*
  • Male
  • Mecamylamine / pharmacology
  • Neurons, Afferent / drug effects*
  • Neurons, Afferent / physiology
  • Nicotine / antagonists & inhibitors
  • Nicotine / pharmacology*
  • Nicotinic Antagonists / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Solitary Nucleus / physiology*
  • Taste / drug effects*
  • Taste / physiology
  • Tongue / drug effects
  • Tongue / innervation


  • Ganglionic Stimulants
  • Nicotinic Antagonists
  • Mecamylamine
  • Nicotine
  • Capsaicin