“Ganglionic blockade with chlorisondamine evoked significantly greater pressor action by L-proline injection than that without treatment, but intravenous injection of the vasopressin antagonist, (d(CH2)5(1), O-Me-Tyr2, Arg8)-vasopressin (10 micrograms/kg), promptly dilated the superior mesenteric vascular bed and lowered the arterial pressure.”