Studies in postmortem dopamine uptake. II. Alterations of the synaptosomal catecholamine uptake in postmortem brain regions in schizophrenia

Abstract

Kinetic parameters KM and Vmax of the synaptosomal high-affinity dopamine (DA) and noradrenaline (NA) uptake were measured in the nucleus (n.) accumbens, n. caudatus and frontal cortex from post-mortem brains of schizophrenic patients and matched controls. Additionally, the 5-hydroxytryptamine (5 HT) uptake was determined in the n. accumbens of the same specimens. The KM and Vmax data of DA uptake were significantly elevated in the n. accumbens (KM to 253%, Vmax to 271%) and in the n. caudatus (KM to 201%, Vmax to 174%) of schizophrenics in comparison with controls. The kinetic parameters of the NA uptake increased similarly in the n. accumbens and n. caudatus of schizophrenics in comparison with controls. The alterations in DA and NA uptake kinetics do not seem to be primarily dependent on neuroleptic medication. On the other hand, DA and NA uptake in the frontal cortex as well as 5 HT uptake in the n. accumbens was unchanged. The results are compatible with the hypothesis that both DA and NA transmission systems are changed in schizophrenia. They give a first indication of presynaptic functional alterations in schizophrenia.