Vascular effects of the peptides PYY and PHI: comparison with APP and VIP.

Local infusions of PYY (3-100 pmol.min-1) caused a slowly developing vasoconstriction of a long duration in the cat submandibular salivary gland. The vasoconstrictor action of PYY was also present after alpha-adrenoceptor blockade and in sympathectomized animals. Local APP infusions caused only weak vasoconstriction. Infusions of PHI and synthetic PHI caused an atropine-resistant submandibular vasodilation. On a molar basis PHI was, however, almost 1000-fold less potent than VIP as vasodilating agent.