The effects of beta-noradrenergic receptor blockade on acquisition of eyeblink conditioning in 3-month-old F344 rats

Neurobiol Learn Mem. 2002 Sep;78(2):246-57. doi: 10.1006/nlme.2002.4063.

Abstract

There is evidence that blocking beta-noradrenergic receptors will cause deficits in some forms of learning. We investigated the effects of systemic injections of 1, 5, and 10 mg/kg doses of propranolol on acquisition of delay eyeblink conditioning in 3-month-old Fischer 344 rats. We presented a 3-kHz, 90-dB tone as a conditioning stimulus and a 6 psi airpuff as our unconditioned stimulus to freely moving rats. We monitored eyelid activity using EMG signals. The treatment subjects were injected with either propranolol or saline 0.5 h prior to daily training sessions. Two groups of control subjects, one receiving injections of saline and one receiving injections of 5 mg/kg propranolol, received daily training sessions with unpaired and randomized presentation of the tone and airpuff. Each daily training session for the treatment groups consisted of 27 paired training trials and 3 conditioned stimulus-alone training trials. Rats injected with saline vehicle or with 1 mg/kg propranolol achieved a 60% or better learned response rate within two training sessions. Rats injected with 5 or 10 mg/kg propranolol never achieved a response rate significantly different from animals that received unpaired, random presentations of the tone and airpuff stimuli. These results agree with prior studies from our lab that have shown a dose-dependent effect of beta-noradrenergic receptor blockade on learning in rabbit eyeblink conditioning as well as in a runway, motor learning paradigm. We believe that the beta-noradrenergic system plays an important role in learning and memory in more than one cerebellar-dependent learning paradigm.

Publication types

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

MeSH terms

  • Adrenergic beta-Antagonists / administration & dosage
  • Adrenergic beta-Antagonists / pharmacology*
  • Animals
  • Blinking / drug effects*
  • Conditioning, Psychological / drug effects*
  • Dose-Response Relationship, Drug
  • Electromyography
  • Learning / drug effects
  • Male
  • Memory / drug effects
  • Propranolol / administration & dosage
  • Propranolol / pharmacology*
  • Rats
  • Rats, Inbred F344
  • Receptors, Adrenergic / drug effects*
  • Time Factors

Substances

  • Adrenergic beta-Antagonists
  • Receptors, Adrenergic
  • Propranolol