Involvement of neuromedin S in the oxytocin release response to suckling stimulus.
We recently identified neuromedin S (NMS) from the rat hypothalamus as an endogenous ligand for the FM-4/TGR-1 receptor distinct from neuromedin U. In the present study, we examined the role of NMS in the oxytocin release response to suckling stimulation by rat pups. Intracerebroventricular (icv) injection of NMS induced cFos expression in the paraventricular nucleus and supraoptic nucleus. Double immunohistochemical analysis revealed induction of cFos expression in a proportion of oxytocinergic neurons in both nuclei. In addition, icv injection of NMS stimulated oxytocin release dose-dependently in intact rats, and increased milk secretion in lactating rats. On the other hand, icv injection of anti-NMS antiserum into lactating rats significantly suppressed suckling-induced milk ejection. These results suggest that, in the rat, endogenous NMS plays an important role in the oxytocin release response to the suckling stimulus.
Sakamoto
Takumi
T
Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Gakuenkibanadai nishi 1, Miyazaki-shi, Miyazaki-ken 889-2155, Japan.
Mori
Kenji
K
Miyazato
Mikiya
M
Kangawa
Kenji
K
Sameshima
Hiroshi
H
Nakahara
Keiko
K
Murakami
Noboru
N
D000818:Animals; D000833:Animals, Suckling; D005260:Female; D008893:Milk Ejection / Q000187:drug effects / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology / Q000502:physiology*; D010121:Oxytocin / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013495:Supraoptic Nucleus / Q000187:drug effects / Q000378:metabolism
D009479:Neuropeptides; D016760:Proto-Oncogene Proteins c-fos; C497950:neuromedin S; D010121:Oxytocin