Effect of amphetamine repeated treatment on the feeding behavior in neuropeptide Y-overexpressing mice.
The preset study examined the hypothesis that an increase of brain neuropeptide Y (NPY), an orexigenic peptide, might decrease the action of amphetamine (AMPH), a well-known anorectic agent. Transgenic mice overexpressing the NPY gene were used to compare with the wild-type control. AMPH-induced anorexia is documented to mediate through the release of dopamine (DA), via an activation of D(1)- and D(2)-subtype receptors, to affect the hypothalamic NPY. Thus, co-administration of D(1)/D(2) agonists was also performed to mimic the action of AMPH. The mice of NPY-overexpressing (NPY-OX) and wild-type groups were administered with AMPH or a combination of D(1)/D(2) agonists repeatedly for 5 days. We found that repeated AMPH administration-induced anorexia in wild-type mice was longer (at the initial 3 days) than that in NPY-OX mice (only at the first day). Moreover, repeated co-administration of D(1)/D(2) agonists significantly exerted a continuous anorectic effect in wild-type mice, but exerted a significant effect only at the first day in NPY-OX mice. These results indicated that the anorectic effect of AMPH decayed faster in NPY-OX mice and suggested that NPY expression by the stimuli could counteract the anorectic effect of AMPH. Thus, NPY can be considered to play a functional role in the regulation of AMPH-induced anorexia in mice.
Kuo
Dong-Yih
DY
Department of Physiology, Chung Shan Medical University, Taichung City, 40201, Taiwan.
Inui
Akio
A
Cheng
Juei-Tang
JT
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D000855:Anorexia / Q000139:chemically induced / Q000188:drug therapy; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D004435:Eating / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects*; D015870:Gene Expression; D006720:Homozygote; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009478:Neuropeptide Y / Q000235:genetics*; D017447:Receptors, Dopamine D1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology; D017448:Receptors, Dopamine D2 / Q000819:agonists / Q000502:physiology
D000697:Central Nervous System Stimulants; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D009478:Neuropeptide Y; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D000661:Amphetamine