Participation of baroreceptor reflexes in blood pressure and sympathetic nerve responses to a synthetic human atrial natriuretic peptide in anesthetized dogs.

The effects of a synthetic alpha human atrial natriuretic polypeptide (hANP) on systemic blood pressure and renal nerve activity were studied before and after sinoaortic denervation with vagotomy in anesthetized dogs. Intravenous injection of hANP (1 microgram/kg) in animals with the neuraxis intact produced a mild decrease in systemic blood pressure and a significant increase in renal sympathetic nerve activity. However, in animals with sinoaortic denervation and vagotomy, a profound fall in blood pressure occurred after administration of hANP. Renal nerve activity in these animals was reduced significantly, in parallel with decreases in systemic blood pressure. These results indicate that activation of peripheral baroreceptors minimizes the hypotension induced by intravenous injection of hANP, and may mask at least centrally mediated cardiovascular effects of hANP.