Association of an odor with activation of olfactory bulb noradrenergic beta-receptors or locus coeruleus stimulation is sufficient to produce learned approach responses to that odor in neonatal rats

Behav Neurosci. 2000 Oct;114(5):957-62. doi: 10.1037/0735-7044.114.5.957.


These experiments examined the sufficiency of pairing an odor with either intrabulbar activation of noradrenergic beta-receptors or pharmacological stimulation of the locus coeruleus to support learned odor preferences in Postnatal Day 6-7 rat pups. The results showed that pups exposed to odor paired with beta-receptor activation limited to the olfactory bulb (isoproterenol, 50 microM) displayed a conditioned approach response on subsequent exposure to that odor. Furthermore, putative stimulation of the locus coeruleus (2 microM idazoxan or 2 mM acetylcholine) paired with odor produced a subsequent preference for that odor. The effects of locus coeruleus stimulation could be blocked by a pretraining injection of the beta-receptor antagonist propranolol (20 mg/kg). Together these results suggest that convergence of odor input with norepinephrine release from the locus coeruleus terminals within the olfactory bulb is sufficient to support olfactory learning.

Publication types

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

MeSH terms

  • Adrenergic beta-Agonists / pharmacology*
  • Animals
  • Animals, Newborn
  • Female
  • Isoproterenol / pharmacology*
  • Learning / drug effects*
  • Learning / physiology*
  • Locus Coeruleus / drug effects*
  • Locus Coeruleus / metabolism*
  • Male
  • Odorants*
  • Olfactory Bulb / drug effects*
  • Olfactory Bulb / metabolism*
  • Rats
  • Rats, Long-Evans
  • Receptors, Adrenergic, beta / metabolism*
  • Smell / drug effects*
  • Smell / physiology*


  • Adrenergic beta-Agonists
  • Receptors, Adrenergic, beta
  • Isoproterenol