Splanchnic release of neuropeptide Y during prolonged exercise with and without beta-adrenoceptor blockade in healthy man.
Plasma levels of neuropeptide Y- (NPY-) like immunoreactivity (Li) and catecholamines in the brachial artery, femoral vein and hepatic vein were monitored during physical exercise in a total of 19 healthy men to detect any local release from the leg and splanchnic region. In addition, propranolol (0.15 mg kg-1 i.v.) was given during exercise to determine whether beta-adrenoceptor blockade influenced the increase in plasma NPY-Li and catecholamines. Leg and splanchnic blood flows were measured using indicator dilution techniques and indocyanine green dye. Graded arm exercise was associated with elevations of arterial plasma NPY-Li (two-fold) and noradrenaline (12-fold) comparable to those previously found during leg exercise. During prolonged leg exercise a significant vasoconstriction and release of NPY-Li and noradrenaline was observed in the splanchnic region while no net exchange was found in the exercising leg where marked vasodilatation occurred. Administration of propranolol during exercise produced a clear-cut additional increase in plasma NPY-Li as well as in noradrenaline and adrenaline. It is concluded that splanchnic vasoconstriction during exercise is associated with a local release of both NPY-Li and noradrenaline. The additional elevation in plasma NPY-Li and catecholamines after propranolol during exercise is probably due to increased nerve activity and/or decreased disposal.
Department of Clinical Physiology, Södersjukhuset, Stockholm, Sweden.
G
G
Ahlborg
J M
JM
Lundberg
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D001132:Arm / Q000098:blood supply / Q000502:physiology; D002395:Catecholamines / Q000097:blood; D004837:Epinephrine / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000502:physiology; D008094:Lithium / Q000097:blood; D008297:Male; D009478:Neuropeptide Y / Q000097:blood*; D009638:Norepinephrine / Q000097:blood; D011433:Propranolol / Q000494:pharmacology; D013152:Splanchnic Circulation / Q000502:physiology*; D013997:Time Factors; D014661:Vasoconstriction / Q000502:physiology; D014781:Viscera / Q000098:blood supply / Q000378:metabolism*
D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D009478:Neuropeptide Y; D008094:Lithium; D011433:Propranolol; D009638:Norepinephrine; D004837:Epinephrine