Bioactive angiotensin peptides.

Angiotensin II is recognised as the principle active peptide of the renin-angiotensin system, exerting effects on fluid and electrolyte homeostasis, and cardiovascular control including neural and long term trophic effects. However, recent studies indicate that other angiotensin peptides such as angiotensin III, angiotensin II (1-7) and angiotensin IV, may have specific actions. Interestingly, recent work involving angiotensin IV demonstrates that this peptide binds to specific receptors and may be involved in memory retention and neuronal development. Furthermore, our demonstration that a globin fragment, LVV-haemorphin-7, binds with high affinity to the angiotensin IV binding site and is abundant in the brain, indicates that this may represent a novel brain neuropeptide system. It now appears, that the renin-angiotensin system is more complex than previously thought and capable of generating multiple, active peptides which elicit numerous diverse actions.