Area postrema neurons are modulated by the adipocyte hormone adiponectin.
Adiponectin is an adipocyte-derived peptide hormone involved in energy homeostasis and the pathogenesis of obesity, including hypertension. Area postrema (AP) lacks a blood-brain barrier and is a critical homeostatic integration center for humoral and neural signals. Here we investigate the role of AP in adiponectin signaling. We show that rat AP expresses AdipoR1 and AdipoR2 adiponectin receptor mRNA. We used current-clamp electrophysiology to investigate whether adiponectin influenced membrane properties of AP neurons and found that approximately 60% of rat AP neurons tested were sensitive to adiponectin. Additional electrophysiology experiments coupled with single-cell reverse transcription-PCR indicated that all neurons that expressed both subtypes of receptor were sensitive to adiponectin, whereas neurons expressing only one subtype were predominantly insensitive. Last, microinjection of adiponectin into AP caused significant increases in arterial blood pressure, with no change in heart rate, suggesting that adiponectin acts at AP to provide a possible link between control of energy homeostasis and cardiovascular function.
Fry
Mark
M
Department of Physiology, Queen's University, Kingston, Ontario, Canada, K7L 3N6.
Smith
Pauline M
PM
Hoyda
Ted D
TD
Duncan
Marnie
M
Ahima
Rexford S
RS
Sharkey
Keith A
KA
Ferguson
Alastair V
AV
D017667:Adipocytes / Q000187:drug effects / Q000502:physiology*; D052242:Adiponectin / Q000008:administration & dosage / Q000502:physiology*; D000818:Animals; D031608:Area Postrema / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D006728:Hormones / Q000008:administration & dosage / Q000502:physiology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface / Q000096:biosynthesis
D052242:Adiponectin; D006728:Hormones; D012333:RNA, Messenger; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface; C504339:adiponectin receptor 1, rat; C506573:adiponectin receptor 2, rat