Orexin receptors are expressed in the adrenal medulla of the rat.
Two recently discovered hypothalamic peptides, orexin-A and orexin-B, play a role as mediators in the central mechanisms that regulate feeding behavior and sleep control. These peptides bind and activate two orexins receptors that belong to the G-protein coupled receptor superfamily. Morphological studies have detected mRNA expression of orexin receptors exclusively in the rat central nervous system. In this paper we demonstrate a strong level of expression of orexin receptor 1 and 2 in the adrenal medulla of the rat by RT-PCR and immunohistochemistry. The results of the present study provide the first evidence showing that the adrenal medulla expresses orexin receptors, and thus appears to be a target tissue for orexins. This could open a new loop in which the central and autonomous nervous system may be involved in body weight homeostasis and sleep control.
López
M
M
Department of Physiology, Faculty of Medicine, University of Santiago de Compostela, Spain.
Señarís
R
R
Gallego
R
R
García-Caballero
T
T
Lago
F
F
Seoane
L
L
Casanueva
F
F
Diéguez
C
C
D000313:Adrenal Medulla / Q000378:metabolism*; D000818:Animals; D015870:Gene Expression; D007150:Immunohistochemistry; D008297:Male; D064446:Orexin Receptors; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D064446:Orexin Receptors; D011498:Protein Precursors; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide