[center:34476851ab]Microinjection of NMDA Receptor Agents into the Central Nucleus of the Amygdale Alters Food Intake in Rats[/center:34476851ab]Abstract
Food intake is the primary factor for body weight regulation in animals. Eating behavior is
known to be modulated by various neurotransmitters and receptors. The central nucleus of
the amygdala (CeA) is the forebrain structures which are important in regulation of ingestive
behavior. There is direct and circumstantial evidence to indicate that some circuits involved
with feeding behavior include glutamatergic elements. The present study examined whether
administration of NMA or MK801 in the CeA alters food intake under deprivation. Animals
were deprived for 24 h before tested for food intake. NMDA glutamatergic receptor agonist,
NMA (N-Methyl-DL-aspartic acid) and its antagonist, MK801 (Dizocilpine hydrogen
maleate) were infused bilaterally, and food intakes were measured for 12 h post-injection.
The intra-CeA injection of NMDA glutamatergic agonist NMA (0.25, 0.5 and 0.75 µg/
rat) showed no effect on cumulative food intake. However, administration of NMDA
glutamatergic antagonist, MK801 (0.25, 0.5 and 1 µg/rat) increased food intake in the
deprived rats. The finding suggest that NMDA receptors in the CeA are responsible for the
glutamatergic modulation of feeding in this nucleus.
Keywords: Food intake, NMDA glutamatergic antagonist, MK801.