Effect of age and neuroleptics on tyrosine hydroxylase-IR in sector CA2 of schizophrenic brain.

The density of TH-IR varicosities was analyzed in the hippocampus of 15 normal controls and 11 schizophrenics. The average density of varicosities in apposition with pyramidal cells and in the neuropil was 30-35% lower in CA2, but not other sectors of schizophrenics. Age was correlated with varicosity density in all sectors, particularly in CA2 where young patients showed a 50% reduction on non-pyramidal cells. Neuroleptic dose showed a negative correlation with the density of varicosities, and notably the dose of young schizophrenics was four times higher than that of older subjects. Thus, antipsychotic dose appears to be associated with a suppression of a normal age-related increase of dopamine projections to CA2 during the early phases of schizophrenia.