Mu-opioid receptor mRNA expression in proopiomelanocortin neurons of the rat arcuate nucleus.
It has been previously demonstrated that the activity of proopiomelanocortin (POMC)-containing neurons in the rat arcuate nucleus is regulated by opiates, but the expression of opioid receptors in POMC neurons has never been reported. In the present study, we have applied a double-labeling in situ hybridization technique to investigate the occurrence of mu-opioid receptor mRNA on POMC neurons. We have found that 20+/-3% of arcuate POMC neurons express mu-opioid receptor mRNA and that the proportion of POMC neurons expressing mu-opioid receptor is higher in the caudal than in the rostral portion of the arcuate nucleus. Our data suggest that POMC neurons might be both auto-regulated by beta-endorphin, and regulated by enkephalins.
Bouret
S
S
INSERM U 422, IFR 22, Neuroendocrinologie et Physiopathologie Neuronale, place de Verdun, Lille Cedex 59045, France. bouret@biserte.lille.inserm.fr
Prevot
V
V
Croix
D
D
Jégou
S
S
Vaudry
H
H
Stefano
G B
GB
Beauvillain
J C
JC
Mitchell
V
V
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism* / Q000648:ultrastructure; D018076:DNA, Complementary / Q000235:genetics; D005246:Feedback; D017403:In Situ Hybridization; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009474:Neurons / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000032:analysis*; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D017450:Receptors, Opioid, mu / Q000096:biosynthesis* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D001615:beta-Endorphin / Q000502:physiology
D018076:DNA, Complementary; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D017450:Receptors, Opioid, mu; D011993:Recombinant Fusion Proteins; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin