Comparison of feeding suppression by the anorexigenic hormones neuromedin U and neuromedin S in rats.
We compared the central mechanisms of feeding suppression by the anorexigenic hormones neuromedin U (NMU) and neuromedin S (NMS) in rats. I.c.v. injection of either NMU or NMS dose dependently decreased 3-h food intake during the first quarter of a dark period. Pretreatment involving i.c.v. injection of a specific anti-NMS IgG blocked the suppression of food intake induced by i.c.v.- and i.p.-injected leptin, but anti-NMU IgG elicited no blockade. Quantitative PCR analysis revealed that i.c.v. injection of NMU or NMS caused a dose-dependent increase in CRH and proopiomelanocortin mRNA expression in the paraventricular nucleus (PVN) and arcuate nucleus (Arc) respectively. In tissue cultures of the Arc, secretion of α-melanocyte-stimulating hormone was stimulated by NMU and NMS, with more potent stimulation by NMS. The time-course curves of the increase in neuronal firing rate in Arc slices in response to NMU and NMS showed almost the same pattern, with a peak 10-15 min after treatment, whereas the time-course curves for the PVN slices differed between NMU and NMS. These results suggest that NMS and NMU may share anorexigenic effects, depending on physiological conditions.
Nakahara
Keiko
K
Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2155, Japan.
Katayama
Tetsuro
T
Maruyama
Keisuke
K
Ida
Takanori
T
Mori
Kenji
K
Miyazato
Mikiya
M
Kangawa
Kenji
K
Murakami
Noboru
N
D000818:Animals; D001067:Appetite Depressants / Q000008:administration & dosage / Q000494:pharmacology*; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism; D004435:Eating / Q000187:drug effects*; D007276:Injections, Intraventricular; D020738:Leptin / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D009479:Neuropeptides / Q000008:administration & dosage / Q000494:pharmacology*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D001067:Appetite Depressants; D020738:Leptin; D009479:Neuropeptides; C497950:neuromedin S; C056900:neuromedin U