Long-term imipramine treatment enhances locomotor and food intake suppressant effects of m-chlorophenylpiperazine in rats.
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.
Aulakh
C S
CS
Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, MD 20892.
Cohen
R M
RM
Hill
J L
JL
Murphy
D L
DL
Zohar
J
J
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects*; D007099:Imipramine / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects*; D013997:Time Factors
D010879:Piperazines; D011985:Receptors, Serotonin; D007099:Imipramine; C015068:1-(3-chlorophenyl)piperazine