Altered norepinephrine regulation in bulimia: effects of pharmacological challenge with isoproterenol

While abnormalities in central norepinephrine regulation may contribute to abnormal eating patterns in bulimia nervosa, alterations in function of the peripheral sympathetic nervous system could contribute to the decreased metabolic rate and increased anxiety responses previously reported in these patients. To assess beta-adrenergic receptor sensitivity in bulimic patients, we studied cardiovascular and hormonal responses to acute pharmacological challenge with intravenously administered isoproterenol. In comparison to healthy controls, binge-abstinent bulimic patients had significantly reduced mean baseline plasma norepinephrine level, pulse rate, and systolic blood pressure, and significantly increased chronotropic responses to isoproterenol infusion. Decreased sympathoneural activity may contribute to a tendency for bulimic patients to maintain body weight despite low caloric intake.