title: Sympathoadrenergic regulation and the adrenoceptor system.
abstract: We investigated the effects of endurance and high-intensity training periods on the plasma catecholamine (CA) concentration at rest; on the basal alpha- and beta-adrenoceptor density, regulation, and function on circulating cells; and on the cardiovascular adaptation in long-distance runners and swimmers. The findings of each period were compared with those of untrained men. Endurance training of the long-distance runners and the swimmers led both to a reduced sympathetic activity at rest, indicated by lower CA values, and to a lower beta-receptor density and responsiveness on circulating lymphocytes and an increased alpha 2-receptor sensitivity on circulating platelets. During the high-intensity training period beta-receptor density and responsiveness increased, alpha 2-receptor sensitivity normalized, and heart rate as well as blood pressure values increased in both trained groups. The basal sympathetic activity remained reduced, but the norepinephrine-to-epinephrine (NE/EPI) ratio increased. The NE/EPI ratio might play an important part in the regulation of adrenoceptor density during these different training periods. Swimming-specific characteristics caused different physiological impacts compared with running training, but an attenuated baroreceptor sensitivity might be indicated in both intensively trained groups.
authors.affiliation: Department of Pathophysiology and Sports Medicine, University of Heidelberg, Federal Republic of Germany.
authors.forename: J
authors.initials: J
authors.lastname: Jost
authors.forename: M
authors.initials: M
authors.lastname: Weiss
authors.forename: H
authors.initials: H
authors.lastname: Weicker
mesh_terms: D000262:Adenylyl Cyclases / Q000097:blood; D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000097:blood; D010806:Physical Education and Training; D010807:Physical Endurance / Q000502:physiology*; D010974:Platelet Aggregation / Q000502:physiology; D011941:Receptors, Adrenergic / Q000502:physiology*; D012420:Running; D013550:Swimming; D013564:Sympathetic Nervous System / Q000502:physiology*
chemical_list: D011941:Receptors, Adrenergic; D000262:Adenylyl Cyclases; D009638:Norepinephrine; D004837:Epinephrine