Effects of caffeine, theophylline and theobromine on scheduled controlled responding in rats

Br J Pharmacol. 1982 Mar;75(3):451-4. doi: 10.1111/j.1476-5381.1982.tb09161.x.


1 Rats were trained to respond under a variable interval 30 s (VI 30) schedule of food reinforcement. Caffeine (0.32-32 mg/kg), theophylline (1.0-56 mg/kg) and theobromine (10-320 mg/kg) in general produced dose-related decreases in operant responding. At relatively low doses, caffeine (1.0 mg/kg) and theophylline (3.2 mg/kg) produced slight but nonsignificant increases in VI 30 responding. 3 The rank order of potency for producing decreases in responding was caffeine greater than theophylline greater than theobromine. 4 Daily caffeine injections (32 mg/kg, i.p.) resulted in the development of caffeine tolerance. This tolerance was characterized by a 6 fold shift to the right in the caffeine dose-effect curve. Saline substitution for the 32.0 mg/kg caffeine maintenance dose resulted in a substantial decrease in responding.

MeSH terms

  • Animals
  • Behavior, Animal / drug effects*
  • Caffeine / pharmacology
  • Conditioning, Operant / drug effects
  • Male
  • Rats
  • Rats, Inbred Strains
  • Reinforcement Schedule
  • Theobromine / pharmacology
  • Theophylline / pharmacology
  • Xanthines / pharmacology*


  • Xanthines
  • Caffeine
  • Theophylline
  • Theobromine