Effects of amino acid deficiency on monoamines in the lateral hypothalamus (LH) in rats.
Animals decrease intake of an indispensable amino acid deficient diet, due in part to decreased dietary limiting amino acid concentrations within the anterior piriform cortex (APC). In addition to studies supporting a primary role for the APC in this phenomenon, recent studies have shown that the lateral hypothalamus (LH), which receives projections from the APC, also mediates the anorectic response to amino acid deficiency. The neurochemical changes within the LH that accompany the anorexia to amino acid deficiency are unclear. We hypothesized that norepinephrine (NE), dopamine (DA) and serotonin, whose levels are altered in response to amino acid deficiency within the APC, also act within the LH to mediate amino acid deficiency-induced anorexia. We determined that ingestion of an amino acid devoid diet increased concentrations of NE and the serotonin metabolite, 5-hydroxyindoleacetic acid in the LH. The 5-hydroxytryptamine metabolite was increased overall, according to analysis by area under the curve. Individual points reached significance at 130 min; NE was elevated at 170 min. These results suggest that the sustained anorectic response following ingestion of an amino acid devoid diet may be associated with increased activity of the NE and 5-hydroxytryptamine systems in the LH.
Blevins
J Ernie
JE
Division of Endocrinology/Metabolism, Department of Veterans Affairs Medical Center, University of Washington, Seattle, WA 91808, USA. jeblevin@u.washington.edu
Teh
Pok S
PS
Wang
Chen X
CX
Gietzen
Dorothy W
DW
D000596:Amino Acids / Q000172:deficiency*; D000818:Animals; D019540:Area Under Curve; D015306:Biogenic Monoamines / Q000378:metabolism*; D004032:Diet; D004563:Electrochemistry / Q000379:methods; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007026:Hypothalamic Area, Lateral / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism
D000596:Amino Acids; D015306:Biogenic Monoamines; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D009638:Norepinephrine