Vasoactive Intestinal Peptide in Sepsis and Shock

The response to trauma, hypovolemia, septicemia, and circulatory collapse depends on a complex interaction between the nervous and humoral systems.'-' Recent investigations have demonstrated several neurotransmitters in both the central and peripheral nervous systems. Accordingly, their possible physiological actions may be responsible for widespread responses in the organism. Vasoactive intestinal polypeptide (VIP) is a 28 amino acid residue peptide originally isolated from porcine intestine by Said and Mutt4 and subsequently recognized as a neurotransmitter substance. Neurons containing VIP-like immunoreactivity have been demonstrated in the central nervous system, lung, and genitourinary tract, as well as in several other organ^.^' The studies of Lillehei and Fine in the sixties suggested the GI tract to be of great importance in the development of irreversible shock. However, uncertainty has been reported with regard to the eventually important substances that might be released from the GI tract in shock.*-" Among other characteristics of the GI tract is the fact that it represents an impressive hormonal organ. Large amounts of VIP-containing neurons are located in the gastrointestinal tract. VIP, which harbors potent vasodilatory effects, could be one of the connections between the classical neural and hormonal systems. In order to evaluate the possible role of VIP in sepsis and shock in general, we have tried to elucidate if-and eventually how-VIP is involved in shock states.