Levodopa and L-Tryptophan Therapy in Parkinsonism

Serotonergic loss in motor circuitries correlates with severity of action-postural tremor in PD

“…Early clinical trials in humans have suggested that agents acting on the 5-HT system, such as HT 2 agonists, can help attenuate tremor in PD. 9,10 Identifying the underlying mechanisms of tremor will allow the development of new optimized therapies for the management of this poorly managed, troublesome symptom for patients with PD.…”

“…Degeneration of the DAergic system is considered the pathologic hallmark of PD and tremor is one of the cardinal symptoms of PD. To date, both animal models 2 and in vivo studies utilizing 18 F-dopa PET 9 and 11 C-raclopride 10 have demonstrated that levels of reduced striatal DA function are not clinically correlated with tremor but rather with bradykinesia and rigidity.…”

“…For example, global tremor scores were found to improve in 40 patients over 8 weeks after administration of tryptophan, a biochemical precursor of 5-HT, in addition to the L-dopa therapy. 9 Additionally, the 5-HT 2 receptor agonist, ritanserin, has also produced an improvement of resting tremor in patients with PD. 10 Herein, we have demonstrated that there is a generalized 5-HT dysfunction in motor-related regions in patients with tremor-predominant PD, and that 5-HT transporter functional loss in caudate, putamen, and raphe nuclei is clinically related to the development of action-postural tremor in these patients.…”

Depression in Patients With Epilepsy

“…Furthermore, a skilled observer, by reason of his training or experience, has standards against which he can evaluate the intensity of any-one symptom, whereas a patient has no such standards: "severe", "moderate" and "mild" have no meaning to a patient, except in relation to his or her own experience. Secondly, although the HDRS was designed for use with patients already diagnosed as suffering from depressive illness, it has also been found useful with general medical patients (Schwab et al 1967b), patients with Parkinsonism (Coppen et al 1972c;Robins 1976) and patients with epilepsy (Roy 1979 Although originating in the USA, the EDI has been validated on English patients (Metcalfe and Goldman 1965), and a cut-off point of 11 has been suggested for British subjects (Metcalfe and Goldman 1965;Salkind 1969). …”

“…It has been used to measure the presence and severity of depression in medical inpatients, including 19 neurological patients (Schwab et al 1967a), patients with Parkinsonism (Coppen et al 1972c) and subjects with physical complaints (Armstrong et al 1980). Salkind (1969) has found the BDI useful in general practice.…”