Leptin modulates noradrenaline release in the paraventricular nucleus and plasma oxytocin levels in female rats: a microdialysis study.
The neural control and mutual interrelationships among individual factors involved in the regulation of food intake and simultaneously related to reproduction are far from being understood. We have suggested that at least some of the effects of orexigenic and anorexigenic peptides might be mediated via noradrenaline release in the paraventricular nucleus (PVN). The main hypothesis was that leptin has an inhibitory action on oxytocin secretion and hypothalamic release of noradrenaline. Non-pregnant female rats in their diestrus were subjected to cannulation of the carotid artery and a microdialysis procedure with the probes in the hypothalamic PVN. Intra-arterial administration of cholecystokinin-8 (CCK) at the dose of 50 mg/kg was used to induce oxytocin and noradrenaline release. Leptin (10 mg/5 ml) was intracerebroventricularly injected in addition to CCK. Blood and microdialysis samples were collected at 20-min intervals for 80 min. Central administration of leptin significantly reduced both plasma oxytocin and hypothalamic noradrenaline responses to CCK at 20 min following the treatments. In conclusion, leptin may inhibit oxytocin secretion by lowering noradrenergic neurotransmission in the PVN. The modulator effect of leptin on noradrenaline release in the PVN may be related to feeding behavior.
Kutlu
Selim
S
Department of Physiology, Firat University, Faculty of Medicine, Elazig, Turkey.
Aydin
Mehmet
M
Alcin
Ergul
E
Ozcan
Mete
M
Bakos
Jan
J
Jezova
Daniela
D
Yilmaz
Bayram
B
D000704:Analysis of Variance; D000818:Animals; D002339:Carotid Arteries; D002404:Catheterization; D002491:Central Nervous System Agents / Q000494:pharmacology; D002766:Cholecystokinin / Q000494:pharmacology; D002845:Chromatography; D005260:Female; D020738:Leptin / Q000378:metabolism*; D017551:Microdialysis; D009638:Norepinephrine / Q000378:metabolism*; D010121:Oxytocin / Q000097:blood* / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D002491:Central Nervous System Agents; D020738:Leptin; D010446:Peptide Fragments; C410885:cholecystokinin 8; D010121:Oxytocin; D002766:Cholecystokinin; D009638:Norepinephrine