Autonomic function in parkinsonian patients relates to duration of disease.

Autonomic functions were studied after withdrawal of all medication in parkinsonian out-patients with short and long duration of disease and in age-matched healthy control subjects. Vagal heart control and noradrenergic response to standing were impaired and related to duration of symptoms of idiopathic parkinsonism. Cholinergic function of pupil motility was unchanged. The cholinergic dysfunction of heart rate variation, therefore, could be due to a specific loss of dopaminergic neurons in the vagal motor nucleus.