Beta-adrenergic-mediated inhibition of feeding by mercaptoacetate in food-deprived rats

Pharmacol Biochem Behav. 2006 Dec;85(4):722-7. doi: 10.1016/j.pbb.2006.11.002. Epub 2006 Dec 15.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adrenergic beta-Antagonists / pharmacology*
  • Animals
  • Fatty Acids / metabolism
  • Feeding Behavior / drug effects
  • Feeding Behavior / physiology*
  • Food Deprivation*
  • Injections, Intraperitoneal
  • Male
  • Oxidation-Reduction
  • Propranolol / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, beta / physiology*
  • Thioglycolates / pharmacology*
  • Vagus Nerve / physiology

Substances

  • Adrenergic beta-Antagonists
  • Fatty Acids
  • Receptors, Adrenergic, beta
  • Thioglycolates
  • 2-mercaptoacetate
  • Propranolol