Vasoactive intestinal peptide (VIP) is a peptide amide containing 28 amino acids which was
first isolated from the intestine and is distributed over the entire body but primarily in the
nervous system. It is released in response to the electrical stimulation of nerve fibres,
stimulation of the vagus, prostaglandin E1, oxytocin, operation stress, corticosterone. In the
cardiovascular system, VIP has a vasodilation, hypotension, positive chronotropic and
inotropic effects.