Enhanced anorexic responses to m-chlorophenylpiperazine during lithium administration to fawn-hooded rats.
In the present study, we investigated whether functional adaptational changes in the serotonergic neurotransmitter mechanisms regulating food intake following long-term lithium treatment in Fawn-Hooded rats (a rat strain suggested to represent a genetic model of depression) were different or similar to those previously observed in Wistar rats. Long-term (21-25 days) lithium treatment accentuated m-chlorophenylpiperazine (m-CPP, a 5-HT agonist) induced decreases in food intake. There was no significant difference in either brain m-CPP concentrations or hypothalamic norepinephrine, dopamine and 5-hydroxyindoleacetic acid concentrations between control and long-term lithium-treated rats following m-CPP. However, hypothalamic serotonin concentrations were significantly higher in long-term lithium-treated compared to saline-treated animals. This finding contrasts with our previous report demonstrating attenuation of m-CPP-induced anorexia in Wistar rats following similar long-term lithium treatment, and therefore suggests a differential adaptation in the serotonergic neurotransmitter mechanisms regulating food intake in a genetic animal model of depression.
Aulakh
C S
CS
Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, MD 20892.
Hill
J L
JL
Murphy
D L
DL
D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology*; D015306:Biogenic Monoamines / Q000378:metabolism; D001923:Brain Chemistry / Q000187:drug effects; D004435:Eating / Q000187:drug effects*; D007031:Hypothalamus / Q000187:drug effects; D008094:Lithium / Q000494:pharmacology*; D008297:Male; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*
D001067:Appetite Depressants; D015306:Biogenic Monoamines; D010879:Piperazines; D017366:Serotonin Receptor Agonists; D008094:Lithium; C015068:1-(3-chlorophenyl)piperazine