Assessment of Adrenergic and Vagal Activity by Plasma Dopamine-β-Hydroxylase and Pancreatic Polypeptide During Exhaustive and Endurance Exercise

Abstract

Plasma dopamine-β-hydroxylase (DBH) and plasma pancreatic polypeptide (PP) have been considered to be indices for adrenergic and vagal activity. Since the autonomic nervous system is affected by both acute and chronic exercise, 10 athletes and 11 control subjects were studied before, during and following exhaustive and endurance bicycle ergometer work. At rest, plasma DBH and PP were similar in both groups, whereas pulse rates were significantly lower in athletes. During exercise, DBH did not increase above basal levels in both tests. Plasma PP increased during exhaustive exercise 3.2- and 2.4-fold in athletes and in controls, respectively. This exercise-induced rise was completely inhibited by the β-blocking agent propranolol. These findings suggest that plasma DBH cannot be used as a measure for sympathetic nervous activity during short-term exercise. Plasma PP levels are better related to adrenergic than to vagal tone although the significance of this in exercise physiology remains to be elucidated.

Key Words

Exercise - dopamine-β-hydroxylase - pancreatic polypeptide - β-receptor blocking - autonomic nervous system