ABSTRACT
Neuropeptide Y (NPY), a tyrosine-rich 36-amino-acid peptide initially isolated from procine brain, is structurally related to a family of peptides including peptide YY and the pancreatic peptide. This chapter presents the investigation of endothelin release during provocations known to evoke, among other responses, the release of vasoconstrictor substances via neuronal reflex mechanisms. Heart rate and blood pressure were monitored continuously during the infusion of NPY or its vehicle. Systemic blood pressure or heart rate were similar in all groups. Infusion of NPY and lipopolysaccharide given alone or in combination were without effect on these parameters. In sham-operated rats, heart rate did not change in response to endotoxin, while mean arterial blood pressure decreased significantly only at the end of infusion. The few reliable studies reporting on the potential mediatory effects of NPY in endotoxemia and septic shock address only two of the criteria designed to ascertain the existence of a causal relationship.
