부산대학교 도서관

Neuropeptide Y (NPY) has prominent cardiovascular effects in mammals and sharks, but no such effect has previously been demonstrated in any teleost fish. In the Atlantic cod, we found that cod NPY ([10.sup.-10]-[10.sup.-6] M) relaxed celiac arteries precontracted with epinephrine, and weak contractions were elicited in intestinal ring preparations. A few NPY-immuno-reactive nerve fibers were present along small gut arteries. The results suggest that cod NPY produces vasorelaxation both by a direct action on smooth muscle and by release of prostaglandins, but with no involvement of nitric oxide, leukotrienes, or endothelium-derived relaxing factors. An additional indirect effect involving another neurotransmitter may occur. Cod NPY ([10.sup.-7] M) and human NPY ([10.sup.-7] M) had identical effects on the vessels. Small differences only in the effects of porcine [[Leu.sup.31],[Pro.sup.34]]NPY, NPY-(13-36), and cod NPY suggest the presence of a [Y.sub.1] subfamily receptor, similar to the zebrafish Ya receptor. A physiological role for NPY in teleost vasculature is concluded, but surprisingly the effect, a vasodilation, is opposite to that in mammals and is mediated by prostaglandins. cod neuropeptide Y; celiac artery; cod intestine; receptor