Diabetes mellitus does not spare brain

Numerous structural, biochemical and behavioral alterations of central nervous system have been demonstrated in diabetes mellitus. The most prominent neurochemical alterations have been observed in monoaminergic transmission, in monoamine content, turnover rate and receptor density Also, some menial and neurological as well as neuroendocrinological disorders whose etiopathogenesis is related to brain monoamine dysfunction are more frequent in diabetes mellitus. Up to now, leading hypothesis has ascribed all monoaminergic alterations to reduced brain uptake of monoamine precursor amino acids. However, regional specificity of monoamine changes, as well as a lack of concomitant regional specificity of blood brain barrier permeability for monoamine precursors in diabetes, argue against this hypothesis. Demonstration of brain insulin system, that has regionally distributed insulin content and brain insulin receptors and specific insulin-monoamine interaction could be a missing link between monoaminergic alterations of central nervous system and diabetes mellitus.