Relationship of Plasma Catecholamines to Peripheral Blood Flow and Thermoregulation during Exercise in the Heat. (Reannouncement with New Availability Information).

摘要

Male rats (350g) were exercised to exhaustion in a climatic chamber (30 deg C) on a motor-driven treadmill (11 m/min, 6 deg incline) to determine the role of adrenergic hormonal activity in the control of blood flow during exercise in the heat. During exercise, significant (P < 0.05) increases occurred in both central and peripheral temperature and blood pressure, metabolic rate and plasma corticosterone. Epinephrine and norepinephrine were only moderately increased. However, at exhaustion both peripheral temperature and blood pressure decreased while the plasma catecholamines levels were significantly (P < 0.05) elevated. We concluded that as the rat approaches hyperthermic exhaustion, a catecholamine-induced vasoconstriction of the tail contributed to sustaining central blood pressure and cardiac output at the expense of peripheral temperature regulation. Blood flow; Thermoregulation; Exercise; Catecholamines; Exhaustion.