Impaired cardiovascular autonomic control in newly and long-term-treated patients with Parkinson's disease: involvement of l-dopa therapy

• Published in: Autonomic neuroscience 2004-11, Vol.116 (1), p.30-38
• Main Authors: Bouhaddi, M., Vuillier, F., Fortrat, J.O., Cappelle, S., Henriet, M.T., Rumbach, L., Regnard, J.
• Format: Article
• Language: English
• Subjects: Aged; Autonomic nervous system; Autonomic Nervous System Diseases - blood; Autonomic Nervous System Diseases - chemically induced; Autonomic Nervous System Diseases - physiopathology; Baroreflex - drug effects; Biological and medical sciences; Blood Pressure - drug effects; Catecholamines - blood; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Fundamental and applied biological sciences. Psychology; Heart Function Tests; Heart Rate - drug effects; Heart rate variability; Humans; l-dopa treatment; Levodopa - adverse effects; Linear Models; Male; Medical sciences; Middle Aged; Neurology; Noradrenaline; Orthostatic hypotension; Parkinson Disease - blood; Parkinson Disease - drug therapy; Parkinson Disease - physiopathology; Parkinson's disease; Peripheral nervous system. Autonomic nervous system. Neuromuscular transmission. Ganglionic transmission. Electric organ; Supine Position; Time; Vertebrates: nervous system and sense organs
• ISSN: 1566-0702; 1872-7484
• DOI: 10.1016/j.autneu.2004.06.009

In idiopathic Parkinson's disease (PD), autonomic dysfunction is frequent, causing orthostatic hypotension. The respective roles of disease progression and dopaminergic treatment remain unclear. In this study, we investigated the autonomic control of cardiovascular functions and its relation to l-dopa therapy in both newly diagnosed (ND) and long-term-treated (LT) patients. Study subjects were: (1) nine ND patients never having undergone treatment with l-dopa; (2) 18 LT patients who had been receiving l-dopa treatment for a long period. ND patients were investigated before l-dopa treatment and after stabilization of their l-dopa dosage. LT patients were investigated once with their regular treatment and once after a 12-h interruption of l-dopa treatment; (3) nine healthy subjects served as controls. At each test session, blood pressure (BP), heart rate (HR), plasma catecholamines, heart rate variability (HRV), and spontaneous baroreflex sensitivity were assessed in the supine and upright positions. Before receiving l-dopa medication, ND patients had reduced E/I ratios (HR response/deep breathing) and lowered HRV when compared to controls; this was evidence of early effects of the disease on autonomic HR control. Introduction of l-dopa treatment reduced BP, HR, and plasma levels of adrenaline and noradrenaline. Similar changes were found in LT patients when contrasting the short-term treatment interruption and the usual l-dopa dosage. The treatment-linked increase in plasma dopamine also correlated with the decrease in noradrenaline. These results showed that mild impairment of autonomic cardiovascular control occurred early in the course of PD. They also provided evidence that the side effects of l-dopa aggravated the impairment of the autonomic control of BP and HR.