Acute fluoxetine administration differentially affects brain C-Fos expression in fasted and refed rats.
In the present study we investigated the effect of acute fluoxetine administration on the expression of c-Fos in the rat brain under two different metabolic conditions: fed and fasting states. Wistar male rats, weighing 220+/-30g, received i.p. injections of saline solution or fluoxetine (10mg/kg), and were killed 2 h later. The brains were removed after transcardiac perfusion with phosphate-buffered saline followed by paraformaldehyde, and were then processed for immunohistochemistry. Fos-like immunoreactivity was quantified by a computerized system. Fasted animals faced an 18-h suppression of food intake, while fed groups were submitted to an initial 14-h period of fast followed by a 4-h period in which food was freely available. Both in fasting and fed states, fluoxetine-treated animals presented a significant increase in c-Fos expression in hypothalamic areas, limbic structures, circumventricular areas, and in mesencephalic and rhomboencephalic regions, as compared with saline-treated controls. The quantitative comparison of data obtained from fasted and fed animals showed that fasted rats treated with fluoxetine presented a higher c-Fos expression in the ventromedial hypothalamus and the paraventricular nuclei compared with the fed group, while in fluoxetine-treated fed rats c-Fos expression was higher in the arcuate nuclei, medial amygdala, locus coeruleus and dorsal raphe nuclei, as compared with fasted, fluoxetine-treated animals. These data indicate that the metabolic condition of the animals significantly modifies fluoxetine-induced brain c-Fos expression, suggesting that visceral and behavioral fluoxetine effects may be influenced by the metabolic state of the individual.
Fraga
I C
IC
Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil.
Fregoneze
J B
JB
Carvalho
F L Q
FL
Dantas
K B
KB
Azevedo
C S
CS
Pinho
C B
CB
de Castro E Silva
E
E
D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D005473:Fluoxetine / Q000008:administration & dosage*; D005508:Food Deprivation / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage
D005473:Fluoxetine; D016760:Proto-Oncogene Proteins c-fos; D017367:Selective Serotonin Reuptake Inhibitors