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Involvement of 5‐HT1A receptors into the dorsal hippocampus in the hypophagic effect caused by fluoxetine in rats
Author(s) -
Scopinho América Augusto,
Aguiar Corrêa Fernando Morgan,
Resstel Leonardo Barbosa Moraes
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1176.2
Subject(s) - fluoxetine , serotonergic , microinjection , serotonin , endocrinology , dorsal raphe nucleus , medicine , 5 ht receptor , antagonist , spiperone , hippocampus , chemistry , serotonin reuptake inhibitor , receptor
Aims Studies showed changes in feeding behavior after lesions of the dorsal hippocampus (DH) suggesting the involvement of this area in the modulation of food intake. Serotonin has been known to play an important role in food intake regulation and the hippocampus receives serotoninergic innervation from the median raphe nucleus. So, the present study examined the effects of the serotonin reuptake inhibitor (fluoxetine) into the DH on food intake and the serotoninergic receptors mediating its effect. Methods Fed and fasted (18 h food‐deprived) male Wistar rats were used. Cannulae were implanted into the DH for injection of drugs: 1) vehicle (aCSF, n=6) or fluoxetine (0.2, 2 or 20 nmol/100 nL, n=6 for each dose); 2) 5‐HT1A receptor antagonist (WAY‐100635, 0.3 nmol/100 nL, n=5) or aCSF (n=5) and fifteen minutes later they received fluoxetine (2 nmol/100 nL) or aCSF. Fifteen minutes later they were submitted to the food intake test (1 hour). Results Our results showed that microinjection of fluoxetine into the DH evoked hypophagic effects in fasted rats (F3,40=78.5, P<0.0001) with a correlation between the doses and reduction in food consumption (r2=0,94, df=14). The microinjection of WAY‐100635 blocked the hypophagic effect caused by fluoxetine into the DH (F=22,5 P<0.0001). Conclusion These results suggest that 5‐HT1A receptors in the DH modulate the hypophagic effect caused by local DH fluoxetine administration.