Cardiorespiratory responses to intracerebroventricular injection of neuropeptide Y in anaesthetised dogs

Cardiovascular and respiratory effects of intracerebroventricular (icv) administration of neuropeptide Y (NPY) and separate, preferential agonists for NPY Y-1 and Y-2 receptors were observed in anaesthetised dogs. Central injections of NPY resulted in significant cardiac slowing and decreases in arterial pressure. These cardiovascular effects were blocked by central injection of the NPY Y-1-preferring antagonist 1229U91. Central injection of NPY did not have a significant effect on ventilation, but the NPY Y-1 antagonist 1229U91 administered alone caused a significant increase in ventilation. The NPY Y-1-receptor agonist [Leu(31)Pro(34)] NPY significantly decreased ventilation while the NPY Y-2 receptor agonist N-acetyl [Leu(28)Leu(31)] NPY 24-36 significantly increased it. A similar inverse relationship was seen with respect red blood pressure, with the NPY Y-1-receptor agonist [Leu(31)Pro(34)] NPY significantly decreasing blood pressure, while the NPY Y, receptor agonist N-acetyl [Leu(28)Leu(31)] NPY 24-36 significantly increased it. These findings suggest a Pole for NPY Y-1 receptors in pathways mediating decreases in ventilation and blood pressure, and for NPY Y-2 receptors in those mediating increased ventilation and blood pressure. (C) 1999 Elsevier Science B.V. All rights reserved.