Effect of L-dopa on human muscle sympathetic nerve activity.

Abstract

This study was undertaken to clarify the mechanism of orthostatic hypotension, one of the side effects frequently encountered after administration of levodopa (L-dopa). Muscle sympathetic nerve activity (MSNA) was measured concomitantly with blood pressure (BP), heart rate (HR) and calf blood flow (calf BF). The responses of these variables to head-up tilting (HUT) were analyzed before and after intravenous administration of L-dopa (50 mg) in eight healthy subjects. L-dopa induced significant increases in MSNA, with concomitant decreases in BP and no changes in calf BF in the supine position. At each angle of HUT, both MSNA and the calf BF increased, following administration of L-dopa. The pattern of MSNA changes was dissociated from that of the calf BF under the influence of L-dopa. These results suggest that peripheral, rather than central, mechanisms are involved in L-dopa-induced orthostatic hypotension.

• Authors: S Takeuchi, Y Sugiyama, T Mano, S Iwase, T Matsukawa
• Journal: Environmental medicine : annual report of the Research Institute of Environmental Medicine, Nagoya University (Environ Med) Vol. 37 Issue 1 Pg. 99-102 ( 1993) ISSN: 0287-0517 [Print] Japan
• PMID: 12269353 (Publication Type: Journal Article)

Chemical References

• Dopamine Agents
• Levodopa

Topics

• Adult
• Blood Pressure (drug effects)
• Dopamine Agents (pharmacology)
• Female
• Heart Rate (drug effects)
• Hemodynamics (drug effects)
• Humans
• Hypotension, Orthostatic (etiology, physiopathology)
• Leg (blood supply)
• Levodopa (adverse effects, pharmacology)
• Male
• Muscles (drug effects)
• Posture (physiology)
• Regional Blood Flow (drug effects)
• Sympathetic Nervous System (drug effects)