The depressor effect of secretin administered either centrally or peripherally in conscious rats

The role of secretin in systemic blood pressure was examined in conscious rats. Either i.c.v. (0.5 or 1.0 micrograms/2 microliter 0.9% saline) or i.v. (1.0 or 2.0 micrograms/10 or 25 microliter saline) administration of secretin in conscious rats resulted in a significant fall in blood pressure. In consideration of previous findings that many other peptides such as substance P, enkephalin, bradykinin, neurotensin and vasoactive intestinal polypeptide cause pressor effects when administered centrally, but produce depressor responses after peripheral administration, the hypotension induced as both central and peripheral effects of secretin is unique and significant.