Salt appetite: interaction of forebrain angiotensinergic and hindbrain serotonergic mechanisms.
Methysergide injected bilaterally into the lateral parabrachial nucleus (LPBN) increases NaCl intake in several models of renin-dependent salt appetite. The present study investigated the role of angiotensin Type 1 (AT1) receptors in the subfornical organ (SFO) on this effect. The intake of 0.3 M NaCl and water was induced by combined administration of the diuretic, furosemide (FURO), and the angiotensin-converting enzyme inhibitor, captopril (CAP). Pretreatment of the SFO with an AT1 receptor antagonist, losartan (1 microgram/200 nl), reduced water intake but not 0.3 M NaCl intake induced by subcutaneous FURO+CAP. Methysergide (4 microgram/200 nl) injected bilaterally into the LPBN increased 0.3 M NaCl intake after FURO+CAP. Losartan injected into the SFO prevented the additional 0. 3 M NaCl intake caused by LPBN methysergide injections. These results indicate that AT1 receptors located in the SFO may have a role in mediating an enhanced sodium intake produced by methysergide treatment.
Menani
J V
JV
Departments of Psychology and Pharmacology and the Cardiovascular Center, University of Iowa, Iowa City, IA 52242-1407, USA.
Colombari
D S
DS
Beltz
T G
TG
Thunhorst
R L
RL
Johnson
A K
AK
D000804:Angiotensin II / Q000502:physiology*; D000818:Animals; D001066:Appetite / Q000187:drug effects / Q000502:physiology*; D002216:Captopril / Q000008:administration & dosage / Q000494:pharmacology; D002404:Catheterization; D005665:Furosemide / Q000008:administration & dosage / Q000494:pharmacology; D007276:Injections, Intraventricular; D007279:Injections, Subcutaneous; D019808:Losartan / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008784:Methysergide / Q000008:administration & dosage / Q000494:pharmacology*; D016548:Prosencephalon / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012249:Rhombencephalon / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D012965:Sodium Chloride / Q000378:metabolism*; D013356:Subfornical Organ / Q000187:drug effects
D000804:Angiotensin II; D012701:Serotonin; D012965:Sodium Chloride; D005665:Furosemide; D002216:Captopril; D019808:Losartan; D008784:Methysergide