Adrenergic signalling between rat taste receptor cells

J Physiol. 2002 Sep 1;543(Pt 2):601-14. doi: 10.1113/jphysiol.2002.020438.

Abstract

In taste buds, synaptic transmission is traditionally thought to occur from taste receptor cells to the afferent nerve. This communication reports the novel observation that taste receptor cells respond to adrenergic stimulation. Noradrenaline application inhibited outward potassium currents in a dose-dependent manner. This inhibition was mimicked by the beta agonist isoproterenol and blocked by the beta antagonist propranolol. The alpha agonists clonidine and phenylephrine both inhibited the potassium currents and elevated intracellular calcium levels. Inwardly rectifying potassium currents were unaffected by adrenergic stimulation. Experiments using the RT-PCR technique demonstrate that lingual epithelium expresses multiple alpha (alpha1a, alpha1b, alpha1c, alpha1d, alpha2a, alpha2b, alpha2c) and beta (beta1, beta2) subtypes of adrenergic receptors, and immunocytochemistry localized noradrenaline to a subset of taste receptor cells. Collectively, these data imply strongly that adrenergic transmission within the taste bud may play a paracrine role in taste physiology.

Publication types

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

MeSH terms

  • Adrenergic alpha-Agonists / analysis
  • Adrenergic alpha-Agonists / pharmacology
  • Adrenergic beta-Agonists / pharmacology
  • Animals
  • Epithelial Cells / physiology
  • Gene Expression
  • Immunohistochemistry
  • Isoproterenol / pharmacology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Neurons, Afferent / chemistry
  • Neurons, Afferent / physiology*
  • Norepinephrine / analysis
  • Norepinephrine / pharmacology
  • Paracrine Communication / drug effects
  • Paracrine Communication / physiology
  • Potassium / metabolism
  • Potassium Channels, Inwardly Rectifying / physiology
  • RNA, Messenger / analysis
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, alpha / genetics
  • Receptors, Adrenergic, alpha / metabolism*
  • Receptors, Adrenergic, beta / genetics
  • Receptors, Adrenergic, beta / metabolism*
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology
  • Taste / physiology*
  • Taste Buds / chemistry
  • Taste Buds / physiology*

Substances

  • Adrenergic alpha-Agonists
  • Adrenergic beta-Agonists
  • Potassium Channels, Inwardly Rectifying
  • RNA, Messenger
  • Receptors, Adrenergic, alpha
  • Receptors, Adrenergic, beta
  • Isoproterenol
  • Potassium
  • Norepinephrine