title: Influence of leptin on neurotransmitter overflow from the rat brain in vitro.
abstract: The 16-kDa polypeptide hormone, leptin along with the neurotransmitters noradrenaline and serotonin (5-HT) have important physiological roles in the regulation of a number of neuroendocrine actions particularly feeding. Leptin receptor mRNA and immunoreactivity has been reported in various brain regions, while recent studies suggest that leptin is released from the human brain. This study investigated the interactions between leptinergic and neurotransmitter systems of the rat brain in vitro. Techniques were established to simultaneously monitor the release of endogenous noradrenaline and its metabolite 3,4 dihydroxyphenylglycol (DHPG), and 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) from the rat brain. The neuromodulatory action of leptin (0.2 and 3 nM) on the overflow of noradrenaline and DHPG from the medulla and hypothalamus was examined. The effect of leptin on 5-HT and 5-HIAA overflow from the hypothalamus was also investigated. Administration of 0.2 and 3 nM leptin significantly increased medullary noradrenaline overflow to 172% and 174% of basal levels, respectively. Leptin had no significant effect on hypothalamic noradrenaline overflow, while leptin perfusion induced a significant increase in 5-HIAA overflow from the hypothalamus. This study lends support to the notion of a complex interaction of the leptinergic and brain neurotransmitters involved in the control of feeding and energy metabolism.
authors.affiliation: Baker Medical Research Institute, Human Neurotransmitter Laboratory, P.O. Box 6492, Victoria 8008, Melbourne, Australia. Jacqueline.Hastings@baker.edu.au
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Hastings
authors.forename: Glen
authors.initials: G
authors.lastname: Wiesner
authors.forename: Gavin
authors.initials: G
authors.lastname: Lambert
authors.forename: Margaret J
authors.initials: MJ
authors.lastname: Morris
authors.forename: Geoff
authors.initials: G
authors.lastname: Head
authors.forename: Murray
authors.initials: M
authors.lastname: Esler
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D020738:Leptin / Q000494:pharmacology*; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives* / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D010477:Perfusion; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D013997:Time Factors
chemical_list: D020738:Leptin; D018377:Neurotransmitter Agents; D012701:Serotonin; D008734:Methoxyhydroxyphenylglycol; D006897:Hydroxyindoleacetic Acid; C010117:3,4-dihydroxyphenylglycol; D009638:Norepinephrine