Decreased sympatho-adrenal activity in diabetic patients with autonomic dysfunction following mental stress.

The sympathetic nervous system is of major importance in the regulation of numerous physiological functions. While it is clearly established that there is a decreased noradrenergic status in people with autonomic neuropathy, the epinephrine secretion is much more controversial. Basal and mental stress-stimulated plasma catecholamine levels were measured in 42 diabetic patients with and without pathological cardiovascular function tests and in 13 healthy, non-diabetic control subjects. In addition, the excretion of catecholamines was measured in a 24 h urine collection and compared with the stress stimulated plasma levels. During mental stress exposure a diminished epinephrine secretion was found in diabetic patients with autonomic neuropathy compared with diabetic patients without neuropathy and the healthy control group (p < 0.05: respectively). The decreased epinephrine response to mental stress was strongly correlated with a diminished urinary excretion of this "neurotransmitter' (r = 0.46; p < 0.01). Diabetic patients suffering from cardiovascular autonomic neuropathy exhibit a diminished sympatho-adrenal response following mental stress exposure. Both measurement of urinary and mental stress stimulated plasma epinephrine levels following mental stress provide reliable information regarding sympatho-adrenal activity in diabetic patients.