[Leu31, Pro34] NPY, a selective functional postjunctional agonist at neuropeptide-Y receptors in anaesthetised rats

Neuropeptide Y (NPY), a sympathetic cotransmitter, has both prejunctional and postjunctional actions in the cardiovascular system. In the bioassay system used here NPY attenuates cardiac vagal action (an indicator of prejunctional or Y2 action) and increases blood pressure (an indicator of postjunctional or Y1 action). [Leu31,Pro34]NPY has little or no prejunctional activity i.e. does not attenuate cardiac vagal action, but increases blood pressure as effectively as NPY. [Leu31,Pro34]NPY can therefore be used in functional experiments to distinguish between the two types of NPY receptor.