Relationship between alpha-melanocyte-stimulating hormone- and neuropeptide Y-containing neurons in the goldfish hypothalamus.
Intracerebroventricular (ICV) injection of alpha-melanocyte-stimulating hormone (alpha-MSH) inhibits, whereas ICV injection of neuropeptide Y (NPY) stimulates food intake in the goldfish. However, there is little information about the functional relationship between alpha-MSH-induced anorexigenic and NPY-induced orexigenic actions in the goldfish. In this study we examined the relationship between alpha-MSH- and NPY-containing neurons in the goldfish hypothalamus to investigate whether these alpha-MSH- and NPY-containing neurons have direct mutual inputs. alpha-MSH- and NPY-like immunoreactivities were distributed throughout the brain, especially in the diencephalon. In particular, alpha-MSH-containing nerve fibers or endings lay in close apposition to NPY-containing neurons in a specific region of the hypothalamus, the nucleus posterioris periventricularis (NPPv). NPY-containing nerve fibers or endings also lay in close apposition to alpha-MSH-containing neurons specifically in the interior part of the nucleus lateralis tuberis (NLTi). We also investigated the effect of ICV injection of melanocortin 4 receptor agonist (melanotan II) at 100 pmol/g body weight (BW), which is enough to suppress food intake, or NPY at 10 pmol/g BW, which is enough to enhance food intake, on expression levels of mRNA for NPY or proopiomelanocortin (POMC) in the hypothalamus. ICV injection of melanotan II and NPY induced a significant decrease in the expression levels for NPY and POMC mRNA, respectively. These observations suggest that alpha-MSH- and NPY-containing neurons share direct mutual inputs in the NPPv and the NLTi of the hypothalamus, and that alpha-MSH and NPY functionally interact or exhibit mutual inhibition to regulate feeding behavior in the goldfish.
Kojima
Kenji
K
Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, Toyama, Toyama 930-8555, Japan.
Amiya
Noriko
N
Kamijo
Motoki
M
Kageyama
Haruaki
H
Uchiyama
Minoru
M
Shioda
Seiji
S
Matsuda
Kouhei
K
D000818:Animals; D002450:Cell Communication / Q000235:genetics / Q000502:physiology; D005260:Female; D005455:Fluorescent Antibody Technique / Q000379:methods; D015870:Gene Expression / Q000187:drug effects; D006054:Goldfish / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006727:Hormone Antagonists / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism* / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D008954:Models, Biological; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000494:pharmacology; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism; D000521:alpha-MSH / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
D006727:Hormone Antagonists; D009478:Neuropeptide Y; D010456:Peptides, Cyclic; C079282:melanotan-II; D000521:alpha-MSH; D011333:Pro-Opiomelanocortin