Neuropeptide Y potentiates the effect of various vasoconstrictor agents on rabbit blood vessels

Abstract

1 The contractile effect of neuropeptide Y (NPY) was tested on isolated segments of basilar artery, central ear artery, gastro-epiploic artery and vein, and femoral artery and vein from the rabbit. At 30 nM NPY did not evoke vasoconstriction; at 300 nM NPY evoked a weak and variable response. 2 NPY greatly potentiated the response of the gastro-epiploic and femoral arteries to noradrenaline without affecting the maximum response. As tested on the gastro-epiploic artery NPY was effective at concentrations of 1 nM and higher. As tested on the femoral artery the potentiating effect of 30 nM NPY on noradrenaline-evoked contractions was apparent immediately and 30 min after the application of NPY, but not after one hour. 3 NPY (30 nM) potentiated the contractile response to noradrenaline and histamine but not to 5-hydroxytryptamine or high K⁺. The response to histamine was augmented in both arteries and veins, whereas the response to noadrenaline was enhanced in arteries but not in veins. NPY failed to potentiate the prostaglandin F_2α-evoked contraction except in the gastro-epiploic vein.