422 THE NEUROSCIENTIST Synaptic Regulation by Angiotensin II Copyright © 2004 Sage Publications

The renin-angiotensin system is well known for its involvement in the short- and long-term regulation of arterial blood pressure. The octapeptide angiotensin II (Ang II) is synthesized from angiotensin I through angiotensin-converting enzyme. Angiotensin I is derived from angiotensinogen by the action of renin released from the juxtaglomerular apparatus of the kidney. The circulating Ang II has several well-recognized actions, including vasoconstriction, stimulation of aldosterone and vasopressin release, generation of thirst and sodium appetite, and feedback regulation of renin release. In addition to its role as a blood-borne hormone, Ang II also is a neuropeptide produced within the central nerv-ous system and may function as a neurotransmitter or modulator to influence the neurotransmission and th