Noradrenaline response to edrophonium (Tensilon) and its relation to other autonomic tests in diabetic subjects

Noradrenaline responses following 10 mg intravenous edrophonium were assessed in 32 insulin-treated diabetic men, allocated to 4 groups according to their responses to 5 cardiovascular autonomic tests. The group with the most severe autonomic involvement had no rise in plasma noradrenaline, in contrast to the other 3 groups, whereas the heart rate fell in all 4 groups. There were significant correlations between individual noradrenaline responses, cardiovascular reflex tests, 24 hour heart rate variation and pupil cycle time, depending on whether predominantly parasympathetic or sympathetic pathways or both were involved. These results indicate that the noradrenaline response to edrophonium cannot be used as a test of early sympathetic dysfunction in diabetics; and that autonomic nervous system involvement occurs simultaneously in different body systems.