dizocilpine-maleate and maltotriose

Rats increase their intake of food, but not water, after intraperitoneal injection of MK-801, a noncompetitive antagonist of N-methyl-D-aspartate-activated ion channels. We hypothesized that MK-801 might enhance intake by interfering with intestinal chemosensory signals. To test this hypothesis, we examined the effect of the antagonist on 15% sucrose intake after an intraduodenal infusion of maltotriose, oleic acid, or phenylalanine in both real- and sham-feeding paradigms. MK-801 (100 microg/kg) significantly increased sucrose intake regardless of the composition of the infusate during real feeding. Furthermore, MK-801 had no effect on reduction of sucrose intake by intestinal nutrient infusions in sham-feeding rats. These results indicate that MK-801 does not increase meal size and duration by interfering with signals activated by intestinal macronutrients.

Topics: Animals; Dizocilpine Maleate; Eating; Excitatory Amino Acid Antagonists; Intestines; Intubation, Gastrointestinal; Male; Oleic Acid; Phenylalanine; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Solutions; Sucrose; Trisaccharides