title: Infusion of nicotine into the LHA enhances dopamine and 5-HT release and suppresses food intake.
abstract: Nicotine administration induces hypophagia. Because of the involvement of hypothalamic neurotransmitters in food intake control, we hypothesized that increased activity of the lateral hypothalamic dopamine (LHA-DA) and/or serotonin (LHA-5-HT) may be responsible for nicotine-induced hypophagia. Either 4 mM nicotine or vehicle was administered via reverse microdialysis technique into the LHA of overnight food-deprived rats for 60 min; then food was provided for 40 min. The LHA-DA, 5-HT and their intermediate metabolites, DOPAC and 5-HIAA, were continuously measured during 20-min intervals before, during, and after nicotine administration. Continuous nicotine administration for 60 min increased LHA-DA and DOPAC concentrations during the first 40 min, and induced a long-lasting increase in LHA-5-HT release, until 120 min after the start nicotine administration, even when nicotine administration was stopped. The food intake during the 40-min refeeding period was significantly lower when rats received nicotine. Eating induced a significant and short-lasting increase in the LHA-DA and a long-lasting increase in the LHA-5-HT. These findings indicate that nicotine enhances dopaminergic and serotonergic activity in the LHA, and that the enhanced LHA-5-HT activity may contribute to nicotine-induced hypophagia.
authors.affiliation: Department of Surgery, University Hospital SUNY Health Science Center at Syracuse, 13210, USA.
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Yang
authors.forename: V
authors.initials: V
authors.lastname: Blaha
authors.forename: M M
authors.initials: MM
authors.lastname: Meguid
authors.forename: A
authors.initials: A
authors.lastname: Oler
authors.forename: G
authors.initials: G
authors.lastname: Miyata
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D004435:Eating / Q000187:drug effects*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007026:Hypothalamic Area, Lateral / Q000187:drug effects / Q000502:physiology*; D008297:Male; D017551:Microdialysis; D008845:Microinjections; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D012701:Serotonin / Q000378:metabolism*
chemical_list: D018722:Nicotinic Agonists; D015102:3,4-Dihydroxyphenylacetic Acid; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D009538:Nicotine; D004298:Dopamine