ANGIOTENSIN-II RECEPTOR SUBTYPES IN THE HUMAN CENTRAL-NERVOUS-SYSTEM

The distribution of the AT(1) and AT(2) subtypes of angiotensin II rec eptor was mapped in the adult human central nervous system using quant itative in vitro autoradiography. Binding in all forebrain, midbrain, pontine, medullary and spinal cord sites where angiotensin II receptor s have previously been described is of the AT(1) subtype, as is bindin g in the small and large arteries in the adjacent meninges and in chor oid plexus. By contrast, both AT(1) and AT(2) receptors occur in the m olecular layer of the cerebellum. Angiotensin II AT(1) receptors in th e brain show a moderate degree of conservation across mammalian specie s studied so far, whereas expression of AT(2) receptors is more variab le, and is more restricted in the human CNS than in many other mammals . These differences between the subtype distributions in humans and ot her animals indicate the need for care when extrapolating the results of animal studies involving the brain angiotensin system.