. "vasoactive intestinal peptide" . . "Vasoactive intestinal peptide" . "vasoactive intestinal peptide (VIP)" . . "SCN and circadian rhythm" . . . . . . . . . . . "Vasoactive Intestinal Peptide" . . . . . . . . . . . "Vasoactive intestinal peptide (VIP)" . . "Vasoactive intestinal peptide" . "vasoactive" . . . "VIP" . . . .