Effect of Glyprolines on Norepinephrine Tone of Isolated Rat Aortic Rings

Glyprolines, short proline-containing peptides (Pro-Gly-Pro, Pro-Gly, and Gly-Pro) in concentrations of 10-8-10-4 M decreased norepinephrine tone of the isolated rat aortic rings. The vasodilatory effect of Pro-Gly-Pro and Pro-Gly was associated with NO release from endotheliocytes, while Gly-Pro directly affected vascular smooth muscle cells.