title: Opioid systems in the lateral hypothalamus regulate feeding behavior through orexin and GABA neurons.
abstract: The hypothalamus controls feeding behavior. Since central opioid systems may regulate feeding behavior, we examined the role of μ-, δ- and κ-opioid receptors in the lateral hypothalamus (LH), the hunger center, in feeding behavior of mice. Non-selective (naloxone; 3 mg/kg, s.c.) and selective μ- (β-funaltrexamine, β-FNA; 10 mg/kg, s.c.), δ- (naltrindole; 3 mg/kg, s.c.) and κ- (norbinaltorphimine, norBNI; 20 mg/kg, s.c.) opioid receptor antagonists significantly decreased food intake in food-deprived mice. The injection of naloxone (20 μg/side) into the LH significantly decreased food intake whereas the injection of naloxone (20 μg/side) outside of the LH did not affect food intake. The injection of β-FNA (2 μg/side), naltrindole (1 μg/side) or norBNI (2 μg/side) into the LH significantly decreased food intake. Furthermore, all these antagonists significantly decreased the mRNA level of preproorexin, but not those of other hypothalamic neuropeptides. In addition, the injection of the GABAA receptor agonist muscimol (5 μg/side) into the LH significantly decreased food intake, and this effect was abolished by the GABAA receptor antagonist bicuculline (50 μg/side). Muscimol (1mg/kg, i.p.) decreased the mRNA level of preproorexin in the hypothalamus. Naloxone (3mg/kg, s.c.) significantly increased the GABA level in the LH and both bicuculline and the GABA release inhibitor 3-mercaptopropionic acid (3-MP, 5 μg/side) attenuated the inhibitory effect of naloxone on feeding behavior. 3-MP also attenuated the effects of β-FNA and norBNI, but not that of naltrindole. These results show that opioid systems in the LH regulate feeding behavior through orexin neurons. Moreover, μ- and κ-, but not δ-, opioid receptor antagonists inhibit feeding behavior by activating GABA neurons in the LH.
authors: Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: C
authors: C
authors: Ardianto
authors: Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: N
authors: N
authors: Yonemochi
authors: Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: S
authors: S
authors: Yamamoto
authors: Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: L
authors: L
authors: Yang
authors: Department of Physiology and Molecular Sciences, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: F
authors: F
authors: Takenoya
authors: Peptide Drug Innovation, Global Research Center for Innovative Life Science, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: S
authors: S
authors: Shioda
authors: International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
authors: H
authors: H
authors: Nagase
authors: Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan. Electronic address: h-ikeda@hoshi.ac.jp.
authors: H
authors: H
authors: Ikeda
authors: Department of Pathophysiology and Therapeutics, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: J
authors: J
authors: Kamei
mesh_terms: D000818:Animals; D005247:Feeding Behavior / Q000502:physiology*; D059330:GABAergic Neurons / Q000502:physiology*; D007026:Hypothalamic Area, Lateral / Q000502:physiology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D017551:Microdialysis; D000068797:Orexins / Q000378:metabolism*; D011957:Receptors, Opioid / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000068797:Orexins; D011957:Receptors, Opioid
keywords: GABA; feeding behavior; lateral hypothalamus; opioid; orexin