Methylphenidate effects on activity-stress gastric lesions and regional brain noradrenaline metabolism in rats.

Methylphenidate (5, 10, or 20 mg/kg/day) or saline were administered to rats in the activity-stress ulcer paradigm. Running-wheel activity and food consumption did not differ among groups. Methylphenidate produced dose-related increases in gastric ulcer severity, decreases in hypothalamic noradrenaline (NA) and increases in 3-methoxy-4-hydroxy-phenylethyleneglycol sulfate (MHPG-SO4) in the hypothalamus, amygdala, hippocampus and thalamus. These results differ markedly from the effects seen with a related substance, d-amphetamine, and suggest different mechanisms of action for these drugs.