Cardiovascular and respiratory functions are regulated by nerve cells in an area of the brainstem called the nucleus of the solitary tract. Dr. Barnes' research is aimed at recording activity in this area of the brainstem in order to determine how it functions. Hypotension and bradycardia can be produced by application of two neuropeptides, substance P and angiotensin II, into this area. The interactions of these two substances and their effects on autonomic nervous system functioning will be studied. This research will contribute to understanding the role of neuropeptides in the control cardiovascular and respiratory functions.