Potentiation of cholinergic transmission in the rat hippocampus by angiotensin IV and LVV-hemorphin-7

Abstract

Recent evidence demonstrates that the fragment of angiotensin II, angiotensin II (3-8) termed angiotensin IV, binds with high affinity to a specific binding site, the AT4 receptor. Intracerebroventricular injection of AT4 receptor agonists improves the performance of rats in passive avoidance and spatial learning paradigms. AT4 receptors and cholinergic neurons are closely associated in regions involved in cognitive processing, such as the hippocampus and neocortex. We therefore postulated that AT4 receptors affect cognitive processing by modulating cholinergic neurotransmission. To test this, we examined the effect of AT4 receptor ligands, angiotensin IV and LVV-hemorphin-7, on potassium-ev..