Imipramine and its metabolites in human brain

A quantitative and qualitative thin-layer chromatographic study of the distribution of imipramine and its metabolites in 13 different regions of the brain in a fatal case of intoxication has been made. A quantitative thin-layer chromatographic method for in situ determination of imipramine and desipramine has been developed. The concentration of imipramine ranged from 4–36 μg g−1 and of desipramine from 0–8 μg g−1 in different parts of the brain. 8 identified and 8 unidentified metabolites were detected in the different parts of the brain. Among the identified were hydroxy-, N-oxide, and iminodibenzyl-metabolites. The metabolic pattern found corresponds closely to the pattern found in human heart tissue and in urine from patients given imipramine.

Effects of ovariectomy and ovarian hormones on RNA base ratios in specific rabbit brain areas

SUMMARY

The ribonucleic acid (RNA) base percentages were estimated in the hypothalamus, amygdala, hippocampus, frontal cortex, cerebellum and spinal cord of adult intact female rabbits, and after ovariectomy followed by replacement therapy with oestradiol-17β, progesterone and oestradiol plus progesterone. The results indicate a lack of effect on the spinal cord, but a variable effect on all other brain regions examined. In response to the various treatments, all regions examined produced RNA very rich in guanosine monophosphate indicating synthesis of specific RNA. The hypothalamus showed the most significant overall changes. Progesterone injections resulted in the most persistent effects of the hormonal treatments employed. Hypotheses are proposed to explain the variable hormonal effects on brain RNA base composition. It is suggested that ovarian hormones produce specific molecular changes in nervous tissue related either to 'receptors' for the hormones or to neural functions related to behavioural phenomena which are mediated by these hormones.

Thiamine triphosphate deficiency in subacute necrotizing encephalomyelopathy

Extracts of tissue fluids from a patient with subacute necrotizing encephalomyelopathy inhibit thiamine pyrophosphate-adenosine triphosphate phosphotransferase of rat brain. Brain tissue from the patient, in contrast to normal brain tissue, contained essentially no thiamine triphosphate, although thiamine and its other phosphate esters were present in normal concentrations. These findings suggest a relation between this disease and thiamine triphosphate.