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Messenger RNA, obtained from post-mortem brain of 10 schizophrenics, five depressed patients and 10 control subjects, was characterised with respect to a number of parameters. It was found that post-mortem delay was not the major factor in determining RNA yield, size (as determined by cDNA synthesis) and biological activity. Biological activity, as determined by in vitro translation in a reticulocyte-lysate system, could be observed using messenger RNA from periods of 0 to 84 hours post-mortem. Two-dimensional gel analysis of the newly-synthesised radiolabelled products obtained from this material revealed several hundred individual species but no consistent degradation of any particular species with post-mortem delay. It is suggested, therefore, that premortem changes are as important as post-mortem changes in determining RNA yield, size and biological activity. Although no consistent difference could be found between patients and controls using any of these parameters, this study confirms that, by isolating messenger RNA from post-mortem human brain, valuable information can be gained on gene expression in psychiatric disorders. [ABSTRACT FROM AUTHOR]

Erythrocytes from lithium treated patients were separated according to the time they had been circulating in the plasma. Choline transport and choline content were measured in the erythrocyte fractions separated according to age, in order to investigate the relationship between decreased choline transport and increased choline content seen in lithium treated patients. The most recently formed erythrocytes of normal subjects had the greatest choline content and the most active choline carrier. The erythrocytes of lithium treated patients had reduced choline carrier activity and increased choline content in all age bands. However the greatest accumulation of choline and least inhibited choline carrier activity was seen in the most recently formed cells. The alteration in phospholipid concentrations measured could not of themselves account for elevated erythrocyte choline levels seen in lithium treated patients. It is concluded that the increase in choline content levels in lithiated erythrocytes does not have a simple inverse relationship with the deficiency in choline transport. The inhibition of the choline carrier is caused by modification due to circulation in lithiated plasma rather than a lack of its synthesis in reticulocytes. [ABSTRACT FROM AUTHOR]