Immunolocalisation of endothelin-1 in human brain

The potent vasoconstrictor endothelin-1 (ET-1) may function as a neuropeptide and be a contributing factor in some neurological disorders, e.g. Alzheimer's dementia. The presence of ET-1 has been studied more extensively in the rat and porcine nervous systems than in the human brain. Also, the recent description of the extensive ET-1 mRNA localisation in human neural tissue supports expression in regions of human brain not previously investigated. Using specific anti-ET-1 polyclonal antiserum, we immunolocalised ET-1 in 24 regions of human brain autopsy tissues, and correlated this with ET-1 mRNA distribution. ET-1 immunoreactivity was observed within some cells of all the 24 areas examined. Neuronal staining for ET-1 was demonstrated within the diencephalon, brainstem, basal nuclei, cerebral cortex, cerebellar hemisphere, amygdala and hippocampus. In addition, ET-1 immunolabelling was visualised in the pituitary gland as well as in the choroid plexus. The primary sensory cortex and pineal gland also contained immunoreactive ET-1, although ET-1 mRNA had never been detected in these regions previously. The localisation of ET-1 and its subsequent correlation with ET-1 mRNA in most of the regions investigated suggest a more extensive distribution of the ET system in the human brain than was previously identified.