L-threo-3,4-dihydroxyphenylserine enhances the orthostatic responses of plasma renin activity and angiotensin II in multiple system atrophy.

We evaluated the effect of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on the response of blood pressure and vasoactive factors during head-up tilt in patients with multiple system atrophy (MSA). After the daily oral administration of 300 mg L-threo-DOPS for 2 weeks we observed a significant reduction in the decline of systolic blood pressure during 60 degrees head-up-tilt. In concordance with this result, we detected significant increases in postural changes in plasma renin activity and angiotensin II following L-threo-DOPS treatment. The enhanced responses of these vasoactive mediators by L-threo-DOPS during head-up tilt may contribute to the improvement in orthostatic hypotension in patients with MSA.