Long-term imipramine treatment enhances locomotor and food intake suppressant effects of m-chlorophenylpiperazine in rats

Br J Pharmacol. 1987 Aug;91(4):747-52. doi: 10.1111/j.1476-5381.1987.tb11272.x.


1 Administration of the 5-HT1B receptor agonist m-chlorophenylpiperazine (m-CPP) to rats produces dose-dependent decreases in locomotor activity and food intake. 2 The locomotor suppressant effect of m-CPP was inhibited by the 5-hydroxytryptaminergic antagonist, metergoline, but not by phentolamine, propranolol, clonidine, or haloperidol. 3 The locomotor suppressant effects of m-CPP were enhanced following long-term (but not short-term) treatment with imipramine, possibly reflecting the postulated development of a functional supersensitivity of 5-HT1B receptors mediating locomotion during longer-term antidepressant drug treatment. 4 The food intake suppressant effects of m-CPP were enhanced following both short (3-5 days) and longer-term (21 days) treatment with imipramine. Rapidly developing 5-hydroxytryptamine uptake inhibition may be responsible for this change, or it may represent an earlier adaptive change in the 5-HT1B receptors mediating food intake compared to more complexly modulated motor responses.

MeSH terms

  • Animals
  • Dose-Response Relationship, Drug
  • Feeding Behavior / drug effects*
  • Imipramine / pharmacology*
  • Male
  • Motor Activity / drug effects*
  • Piperazines / pharmacology*
  • Rats
  • Rats, Inbred Strains
  • Receptors, Serotonin / drug effects*
  • Time Factors


  • Piperazines
  • Receptors, Serotonin
  • Imipramine
  • 1-(3-chlorophenyl)piperazine