Circulating neuropeptide Y in humans: relation to changes in catecholamine levels and changes in hemodynamics.
Neuropeptide-Y (NPY) is a sympathetic cotransmitter, which causes vasoconstriction, decreases coronary blood flow and decreases cardiac output. Circulating immunoreactive NPY (ir-NPY) levels increase with exercise, in patients admitted to the coronary care unit, and during thoracic surgery, and may play a role in postoperative hemodynamics. We studied changes in ir-NPY, epinephrine (E) and norepinephrine (NE) arterial plasma levels, and their correlation to simultaneous hemodynamic measurements at 8 perioperative time points in 13 patients undergoing open heart surgery. Changes in circulating ir-NPY negatively correlated with changes in systemic vascular resistance index (SVRI), mean arterial pressure (MAP) and mean pulmonary arterial pressure (MPAP) (P < 0.05), suggesting that the hemodynamic changes were the cause of the changes in ir-NPY levels, inducing overflow of NPY into the circulation via sympathetic activation. Changes in NE and E levels positively correlated with changes in heart rate (HR), SVRI and MPAP. Changes in E levels also positively correlated with changes in stroke volume index (SVI), central venous pressure (CVP) and cardiac index (CI). NE levels correlated well with E levels, but catecholamine levels did not correlate with ir-NPY levels. These results suggest, that the elevation in circulating NPY levels previously noted in patients with heart failure and acute myocardial infarction may reflect changes in NPY overflow and/or clearance secondary to increased sympathetic activity and to hemodynamic changes.
Hauser
G J
GJ
Division of Pediatric Critical Care Medicine, Georgetown University Children's Medical Center, Washington DC, USA.
Danchak
M R
MR
Colvin
M P
MP
Hopkins
R A
RA
Wocial
B
B
Myers
A K
AK
Zukowska-Grojec
Z
Z
D001794:Blood Pressure; D004837:Epinephrine / Q000097:blood*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009478:Neuropeptide Y / Q000097:blood*; D009638:Norepinephrine / Q000097:blood*; D011651:Pulmonary Artery / Q000502:physiology
D009478:Neuropeptide Y; D009638:Norepinephrine; D004837:Epinephrine