For many years, we have been studying, in psychiatric conditions, the influx of tyrosine (TYR) and tryptophan (TRP), the two amino acid precursors of monoamines, across the membrane of human blood cells. We have also attempted to characterize better the transport mechanisms. In a previous paper, we suggested a close relationship between glucose and the two neuter amino acid transports in vitro. The purpose of the present study is to test the effect of cytochalasin B, the specific and potent inhibitor of glucose transport. Our data show that at high concentrations, the cytochalasin B induces a reversible inhibition of about 70% or more on the temperature-dependent influx of the two amino acids, depending on the medium of incubation. The effect of cytochalasin B was about 200 times less for TYR and TRP transport than for glucose. The cytochalasin E, claimed to be a nonspecific inhibitor, decreased both these transports only when used at very high concentrations, as described for sugar influx in the same structure. In conclusion, we suggest that there is a relationship between the transport of glucose and nucleosides, both carried into the cells by the glycoprotein band 4.5, and the two amino acid precursors of monoamines.

Adult↗

PubMedDate not supplied

[Erythrocyte membrane transport of amino acid precursors of monoamines in schizophrenic patients. Comparison with depressive patients].

The study concerned 72 schizophrenic and 200 depressed patients hospitalised between 1983 and 1990. The erythrocyte membrane transports (EMT) of L-tyrosine and L-tryptophan (at 37 degrees, 0 degrees and 37-0 degrees) of schizophrenics without treatment nor depression were different compared to controls and depressed patients. The schizophrenics under neuroleptic treatment and/or depressed showed same means of EMT values as depressed patients. The slopes of the correlations between EMT of tyrosine or tryptophan at 37 degrees, 0 degrees and 37-0 degrees, as well as that between plasma levels of these amino acids, were parallel. However the slopes of the correlations between EMT of tyrosine and tryptophan were different according to the subgroups of patients: the perturbations of EMT were related to the clinical characteristics. In depressed patients and in schizophrenic patients under neuroleptic treatment and/or depressed, little changes in EMT of tyrosine were related to high changes of EMT of tryptophan.

Antipsychotic Agents↗

PubMedDate not supplied

[Plasma levels and membrane transports in red blood cell of tyrosine and tryptophane in depression. Evaluation at baseline and recovery].

The erythrocyte membrane transports (MT) of L-tyrosine and L-tryptophan, as well as their plasma levels, were measured in 143 depressed patients after a wash-out period of one week and before any antidepressant treatment, and then at regular intervals until they recovered. 49 normal subjects served as a control group. The perturbations of these biologic variables at baseline were different according to diagnostic groups (DSM III), compared to controls: significant decrease of the two MT in depressed bipolar disorders; significant decrease of MT in depressed bipolar disorders; significant decrease of MT tyrosine and significant increase of MT tryptophan in recurrent major depressions; no significant changes of MT in dysthymic disorders. The plasma levels of tyrosine and total tryptophan show a significant diminution in the 3 groups. The study of the evolution of these same variables after antidepressant treatment show a return to normal of the MT at recovery, as well as the plasma levels of tyrosine. The plasma levels of tryptophan stay low in depressed bipolar disorders and recurrent major depressions.

Adult↗

PubMedDate not supplied

[Plasma MHPG, peripheral noradrenergic marker and hormonal plasma levels of cortisol-T3-T4-TSH in depressive syndromes].

Based on the hypocatecholaminergic hypothesis in the depressive syndromes, this survey on 30 depressed patients compared to 21 control patients, attempts to state exactly the potential interactions between the noradrenergic system and the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid neuroendocrine axis. The biological indices used during this survey are: total plasmatic MHPG, the basic plasmatic cortisol, the thyroid hormones T3, T4, free T4, and the TSH. The results of this survey reveal a significative increase of the basic plasmatic cortisol among the depressed patients, including dysthymics, a decrease of the plasmatic MHPG during major depressions, and a significant fall of the total T3 among depressed men, as well as some correlations between the different axes, the interpretation of which remains "ticklish".

Adult↗