Adrenomedullin acts in the rat paraventricular nucleus to decrease blood pressure.

Adrenomedullin is a recently discovered peptide involved in the control of fluid and electrolyte homeostasis and cardiovascular function through peripheral and central nervous system actions. The present study was undertaken to examine the cardiovascular effects of adrenomedullin microinjection directly into the paraventricular nucleus (PVN). Microinjection of adrenomedullin into the PVN of urethane anaesthetized male Sprague-Dawley rats resulted in site-specific, repeatable decreases in blood pressure. These hypotensive effects were found to be dose related, and were not mediated by activation of calcitonin gene-related peptide receptors. These data suggest that adrenomedullin influences cardiovascular regulation through receptor mediated actions at the PVN of the hypothalamus.