Chapter 7 - Angiotensin-Converting Enzyme in the Human Brain

Abstract

This chapter discusses angiotensin-converting enzyme (ACE) in human brain, which converts angiotensin I (Ang I) to angiotensinII (Ang II), a peptide important in the central regulation of blood pressure and fluid and electrolyte homeostasis. Moderate binding is found in the substantia innominata and high intensity of labeling is also present in fibers that exit from the medial part of the internal globus pallidus. The gelatinosus subnucleus of the spinal trigeminal nucleus displays moderate binding as do all the subdivisions of the inferior olivary nucleus. The circumventricular organs have deficient blood–brain barriers and therefore, ACE is responsible for either the conversion of blood-borne Ang I or the production of endogenous neuronal Ang II to influence central mechanisms involved in fluid and electrolyte balance and blood pressure control. Receptors for Ang II are in high concentrations in the human paraventricular nucleus. The overall pattern of ACE distribution in the human brain has high concentrations of enzyme found in the basal ganglia.