Infusion of nicotine into the LHA enhances dopamine and 5-HT release and suppresses food intake.

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.

Relationship between interleukin-1 and cancer anorexia.

Interleukin-1 (IL-1) induces anorexia via direct action in the brain, and its participation in the pathogenesis of cancer-associated anorexia has been hypothesized. Because the functional ablation of the ventromedial nucleus of hypothalamus (VMH), where IL-1 receptors have been detected, reverses cancer-associated anorexia in tumor-bearing (TB) rats, we hypothesize that cancer anorexia involves the direct effect of IL-1 on the VMH. To test this hypothesis, we investigated whether the intra-VMH injection of the IL-1 receptor antagonist (IL-1ra) improves food intake in anorectic TB rats.

Hepatic vagus does not mediate IL-1 alpha induced anorexia.

Peripherally infused interleukin-alpha (IL-1 alpha) reduces food intake. Since the innervated liver modulates eating activity via the vagus, we investigated the role of the hepatic vagus in the etiology of IL-1 alpha induced anorexia. Ten male Fischer 344 rats were randomly assigned to hepatic vagotomy (HX-IL-1 group) or sham operation (Sham-IL-1 group), and an internal jugular catheter was inserted in all rats.

LHA dopaminergic activity in obese and lean Zucker rats.

Microdialysis was performed to quantitate lateral hypothalamic dopamine (LHA DA) release before, during and after a single meal in food-deprived obese and lean Zucker rats to examine our hypothesis that an abnormally high dopamine activity may exist in the LHA of obese Zucker rats. Food consumption after food deprivation, was significantly greater in obese than in lean rats (4.1 +/- 0.

Change in meal size, number and duration after neural isolation of liver and with TPN.

The abundant neural connections between the liver and hypothalamus suggest that the liver contributes to spontaneous food intake (SFI) regulation. This hypothesis was tested in rats after total liver denervation (TLD) and infusing TPN. A sham operation (SO) or TLD was performed in Fischer rats, placed in metabolic cages fitted with an Eater Meter to measure SFI, meal number (MN), size (MZ), and duration (MD).