Cardiovascular actions of neuropeptide Y and social stress

The role of central neuropeptide Y (NPY) in the cardiovascular response to social stress was evaluated in freely moving rats using telemetry. In unstressed rats, intracerebroventricular (ICV) administration of NPY and the selective Y1 receptor agonist [Leu31, Pro34]-NPY decreased blood pressure and heart rate, while the selective Y2 agonist NPY13-36 transiently raised blood pressure. NPY and [Leu31, Pro34]-NPY blunted elevations in blood pressure and pulse rate following exposure to the resident-intruder procedure, an established social stress paradigm. In contrast, the Y2 agonist significantly augmented stress-induced pressor effects. These observations indicate that the hypotensive effects of ICV NPY appear to be mediated by the Y1 receptor subtype and the NPY receptor subtypes may mediate opposing cardiovascular actions in response to stressful stimuli.