Enhancement of systemic and pulmonary vasoconstriction by beta-amyloid peptides and its suppression by vasoactive intestinal peptide.

(1) A beta peptides potentiate vasoconstriction, caused by norepinephrine, and possibly other endogenous vasoconstrictors. If this potentiation occurs in the cerebral circulation, close to sites of A beta deposition in AD brains, the enhanced vasoconstriction could result in neuronal ischemia and death. (2) By neutralizing this deleterious effect of A beta, and through other neuroprotective mechanisms, VIP may provide an important defense against neuronal loss in AD.