What if levodopa's action comes, not from recharging dopamine stores but from a short term lowering of cortisol? Read on....

1: J Neural Transm. 2006 Aug 24; [Epub ahead of print]

Acute levodopa administration reduces cortisol release in patients with
Parkinson's disease.

Muller T, Welnic J, Muhlack S.

Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Bochum,
Germany.

Levodopa (LD) application improves motor symptoms in patients with Parkinson's
disease (PD) patients. Little is known on further effects of LD, which induced
lower plasma levels of cortisol and lower serotonergic activity in certain brain
areas of fish. Objectives of this trial were to analyse levels of cortisol, LD
and 3-O-methyldopa (3-OMD) after administration of LD/benserazide in long term
treated PD patients. 12 PD patients, taken off their regular treatment for at
least 12 hours, received soluble 200 mg LD/50 mg benserazide under stress free
conditions. Motor symptoms improved, LD and 3-OMD levels increased, whereas
cortisol concentrations started to decrease significantly 30 minutes after LD
intake. This reduced cortisol release may result from an overflow of exogenous
LD in the brainstem. This hypothetically causes an reduced 5-HT content in
neurons projecting to the hypothalamic structures, which are involved in the
partial 5-HT dependent central regulation of peripheral cortisol release.

PMID: 16932991 [PubMed - as supplied by publisher]