Psychological, cardiovascular, and endocrine changes during 6 hours of continuous infusion of epinephrine or norepinephrine in healthy volunteers

Psychological, cardiovascular, endocrine, and metabolic reactions to a sustained infusion of epinephrine (E) and norepinephrine (NE) were studied in 10 healthy male volunteers in a placebo-controlled randomized design. The subjects participated each in three sessions during which they received 6-hr infusion of either E (82 pmol/kg/min), NE (178 pmol/kg/min), or placebo (PLA) (saline, 5.4 ml/hr). Heart rate and intra-arterial blood pressure were recorded continuously. Blood samples for assay of catecholamines, cortisol, prolactin, growth hormone, insulin, triglycerides, and glucose were obtained at regular intervals. Changes in subjective mood were assessed with the Profile of Mood States (POMS) and the State-Trait Anxiety Inventory (STAI). During infusion of E, arterial plasma epinephrine levels increased 10-fold, which induced significant increases in heart rate, plasma insulin, and glucose levels, and decreases in mean arterial pressure (MAP) and diastolic pressure (DAP). NE infusion caused a 5-fold arterial plasma norepinephrine increase and induced a significant decrease in heart rate and increases in MAP, DAP, and glucose levels. The effects were present shortly after initiation of the infusions, remained fairly constant during the 6-hr infusion period and disappeared within 1 hr after the infusions had been stopped. Changes in subjective mood were not observed during the infusions, nor after the infusions had been stopped. Infusion of E or NE also had no significant effect on systolic blood pressure, plasma prolactin, growth hormone, cortisol, and triglycerides. Our results show that moderate cardiovascular and metabolic effects can be caused by sustained increases in circulating catecholamines. The psychological parameters were not affected by a prolonged increase in circulating catecholamines in the high physiological range, which extends previous observations concerning the absence of mood changes to short-lasting catecholamine-infusions in healthy subjects.