An examination of the behavioural specificity of hypophagia induced by 5-HT1B, 5-HT1C and 5-HT2 receptor agonists using the post-prandial satiety sequence in rats

Psychopharmacology (Berl). 1994 Jan;113(3-4):369-77. doi: 10.1007/BF02245211.


Previous studies have shown that administration of 5-HT1B, 5-HT1C or 5-HT2 agonists decreases food intake in rats. However, it has not been established whether these drugs induce satiety or decrease feeding by a non-specific mechanism. In the present study the post-prandial satiety sequence was used to characterise the actions of the 5-HT2 receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), the 5-HT1B/5-HT1C receptor agonists, 1-(3-chorophenyl) piperazine (mCPP) and 1-[3-(trifluoromethyl)phenyl] piperazine (TFMPP), and the 5-HT1B agonist, 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)H-indole (RU 24969), on feeding in rats. All four compounds reduced food intake in rats that had been food deprived overnight. The 5-HT1B/5-HT1C agonists, TFMPP (at a dose of 1.0 mg/kg) and mCPP (at a dose of 3.0 mg/kg), appeared to produce satiety as their effects on the satiety sequence were similar to those induced by a food pre-load. In contrast, the 5-HT1B agonist RU 24969 and the 5-HT2 agonist DOI did not produce behavioural profiles that resembled satiety. Thus, RU 24969 elevated active behaviours and did not accelerate resting whereas DOI appeared to induce hypophagia by a non-specific fragmentation of behaviour. The results suggest that simultaneous activation of 5-HT1B and 5-HT1C receptors may be sufficient to elicit behaviourally specific satiety in the rat. In contrast, selective activation of 5-HT2 receptors does not induce satiety but elicits active behaviours and decreases feeding by response competition.

MeSH terms

  • Amphetamines / pharmacology
  • Animals
  • Eating / drug effects
  • Feeding Behavior / drug effects*
  • Grooming / drug effects
  • Indoles / pharmacology
  • Male
  • Motor Activity / drug effects
  • Piperazines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Satiety Response / drug effects*
  • Serotonin Receptor Agonists / pharmacology*


  • Amphetamines
  • Indoles
  • Piperazines
  • Serotonin Receptor Agonists
  • 1-(3-trifluoromethylphenyl)piperazine
  • 5-methoxy 3-(1,2,3,6-tetrahydro-4-pyridinyl)1H indole
  • 4-iodo-2,5-dimethoxyphenylisopropylamine
  • 1-(3-chlorophenyl)piperazine