Beta-adrenergic-mediated inhibition of feeding by mercaptoacetate in food-deprived rats.
This study investigated the effect of intraperitoneal (IP) injections of the fatty acid oxidation (FAO) inhibitor mercaptoacetate (MA, 45.6 mg/kg) on feeding in food-deprived rats. As previously, MA significantly stimulated feeding in ad libitum-fed rats. MA, however, reduced feeding in 18 and 36 h-fasted rats despite apparently antagonizing the fasting-induced increase in hepatic FAO. To test whether this anorectic effect involves beta-adrenergic stimulation, 36 h-fasted rats were IP injected with the nonspecific beta-adrenergic receptor antagonist propranolol (PROP, 0.5 mg/kg) just before MA injection. PROP attenuated MA's feeding-inhibitory effect, suggesting that MA anorexia is at least partially mediated by beta-adrenergic stimulation. Finally, we evaluated the role of subdiaphragmatic vagal afferent fibers in MA's feeding-inhibitory effect by testing the ability of MA to inhibit food intake in fasted rats after subdiaphragmatic vagal deafferentation (SDA). MA inhibited feeding similarly in SDA rats and sham-operated rats. These data demonstrate that subdiaphragmatic vagal afferents are not necessary for the feeding-inhibitory effect of peripheral MA. These results suggest that the FAO inhibitor MA elicits a feeding-inhibitory effect in fasted rats that is mediated by a different mechanism than its feeding-stimulatory effect.
Brandt
Karsten
K
Institute of Animal Sciences, ETH Zurich, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland.
Arnold
Myrtha
M
Geary
Nori
N
Langhans
Wolfgang
W
Leonhardt
Monika
M
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D005227:Fatty Acids / Q000378:metabolism; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D005508:Food Deprivation; D007274:Injections, Intraperitoneal; D008297:Male; D010084:Oxidation-Reduction; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D013864:Thioglycolates / Q000494:pharmacology*; D014630:Vagus Nerve / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D005227:Fatty Acids; D011943:Receptors, Adrenergic, beta; D013864:Thioglycolates; C017487:2-mercaptoacetate; D011433:Propranolol