Splanchnic release of neuropeptide Y during prolonged exercise with and without β‐adrenoceptor blockade in healthy man

摘要

Summary.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 kg1i.v.) was given during exercise to determine whether P‐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 a