The tuberal lateral hypothalamus is a major target for GABAA--but not GABAB-mediated control of food intake

Brain Res. 2009 Aug 4;1283:65-72. doi: 10.1016/j.brainres.2009.05.064. Epub 2009 Jun 6.

Abstract

The lateral hypothalamus (LH) is a site of integration for control mechanisms of feeding behavior as it has extensive reciprocal connections with multiple intrahypothalamic and extrahypothalamic brain areas. Evidence suggests that blockade of ionotropric gamma-aminobutyric acid (GABA) receptors in the LH elicits eating in satiated rats. To determine whether this GABA(A) receptor antagonist effect is specific to the LH, the antagonist picrotoxin was injected into one of six nearby sites and food intake was measured. Picrotoxin at 133 pmol elicited eating in the LH, but not in surrounding sites (thalamus, lateral preoptic area, ventral tegmental area, dorsomedial hypothalamus, and entopeduncular nucleus). More specifically, picrotoxin injected into the tuberal LH (tLH) elicited eating, but was ineffective when injected into the anterior or posterior LH. We also investigated whether GABA(B) receptors in the LH participated in the control of food intake and found that neither blockade nor activation of these receptors under multiple conditions changed food intake. Collectively, our findings suggest that GABA(A) but not GABA(B) receptors in the tLH act to suppress feeding behavior.

MeSH terms

  • Animals
  • Appetite Regulation / drug effects
  • Appetite Regulation / physiology*
  • Feeding Behavior / drug effects
  • Feeding Behavior / physiology
  • GABA Antagonists / pharmacology
  • Hypothalamic Area, Lateral / drug effects
  • Hypothalamic Area, Lateral / metabolism*
  • Male
  • Neural Inhibition / drug effects
  • Neural Inhibition / physiology*
  • Picrotoxin / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, GABA-A / drug effects
  • Receptors, GABA-A / metabolism*
  • Receptors, GABA-B / drug effects
  • Receptors, GABA-B / metabolism
  • gamma-Aminobutyric Acid / metabolism*

Substances

  • GABA Antagonists
  • Receptors, GABA-A
  • Receptors, GABA-B
  • Picrotoxin
  • gamma-Aminobutyric Acid