Abstract
Neuropeptide Y (NPY) is a potent vasoconstrictive polypeptide colocalized with norepinephrine in sympathetic neurons. The effects of ischemia and reperfusion on plasma NPY levels were studied and compared in the mongrel dog after infrarenal aortic cross-clamping. We found a two-to threefold increase in NPY levels during ischemia (initial 10.0 ± 1.8 pmol/L vs. maximum 24.7 ± 2.31 pmole/L, p<0.001). The increase in NPY remained following reperfusion (initial 10.0 ± 0.8 pmole/L vs. maximum 23.9 ± 2.31 pmole/L, p<0.001). These data reveal that NPY is released during ischemia and reperfusion and may be involved in mediating remote vascular events associated with infrarenal aortic cross-clamping.