title: A reassessment of the role of serotonergic system in the control of feeding behavior.
abstract: The role of serotonergic system in the feeding behavior was appraised by electrolytic lesions in the dorsal raphe nucleus (DRN) and administration of para-chlorophenylalanine (PCPA, 3 mg/5 microl, icv). Chronic evaluations were accomplished through 120 and 360 days in PCPA-injected and DRN-lesioned rats, respectively. Acute food intake was evaluated in fasted rats and submitted to injection of PCPA and hydroxytryptophan (LHTP, 30 mg/kg, ip). DRN-lesioned rats exhibited 22-80% increase in food intake up to sixth month, whereas the obesity was evident and sustained by whole period. In PCPA-injected rats was observed an initial increase in the food intake followed by hypophagy from 25th to 30th day and a transitory increase of body weight from 5th to 60th day. In the acute study, the LHTP reverted partially the PCPA-induced increase in food intake of fasted rats suggesting a sustained capacity of decarboxylation of precursor by serotonergic neurons. Slow restoration of the levels of food intake in DRN-lesioned rats reveals a neuroplasticity in the systems that regulate feeding behavior. A plateau on the body weight curve in lesioned rats possibly represents the establishment of a new and higher set point of energetic balance.
authors.affiliation: Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro, BR 465, Km 07, 23890-000, Seropédica, RJ, Brazil.
authors.forename: Magda A
authors.initials: MA
authors.lastname: Medeiros
authors.forename: Ricardo H
authors.initials: RH
authors.lastname: Costa-e-Sousa
authors.forename: Emerson L
authors.initials: EL
authors.lastname: Olivares
authors.forename: Wellington S
authors.initials: WS
authors.lastname: Côrtes
authors.forename: Luís C
authors.initials: LC
authors.lastname: Reis
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000818:Animals; D004572:Electrolysis; D005247:Feeding Behavior / Q000187:drug effects*; D010134:Fenclonine / Q000494:pharmacology*; D008297:Male; D008845:Microinjections; D009765:Obesity / Q000503:physiopathology; D011903:Raphe Nuclei / Q000187:drug effects / Q000293:injuries / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012702:Serotonin Antagonists / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D012702:Serotonin Antagonists; D006916:5-Hydroxytryptophan; D010134:Fenclonine