[Erythrocyte membrane transports of monoamine precursor amino acids in schizophrenia]

We have determined the erythrocyte membrane uptake of the monoamine precursors L-tyrosine (L-TYR) and L-tryptophane (L-TRYP) in 72 patients with schizophrenia: 21 without neuroleptic treatment and not depressed, 15 with neuroleptic treatment and depressed, 33 without neuroleptic treatment, 27 depressed, compared to: 59 control subjects, and 54 depressed patients. We found that the ratio of L-TYR facilitated membrane diffusion to that of L-TRYP is: decreased when the patients are depressed, increased when they are untreated. When untreated patients receive neuroleptics and are depressed, the ratio tends to equal that of depressed patients'. The meaning of these anomalies is analysed, using our up-to-date knowledge of the erythrocytes's role in uptaking and dispatching the human body amino-acids, and of the role of these uptakes in regulating the functional monoamine balance. We postulate that in depressions, Parkinson's disease and schizophrenia, a change of membrane fluidity occurs, being decreased in depressions and Parkinsons's disease, and increased in schizophrenia.