title: Exercise training modulates functional sympatholysis and α-adrenergic vasoconstrictor responsiveness in hypertensive and normotensive individuals.
abstract: Essential hypertension is linked to an increased sympathetic vasoconstrictor activity and reduced tissue perfusion. We investigated the role of exercise training on functional sympatholysis and postjunctional α-adrenergic responsiveness in individuals with essential hypertension. Leg haemodynamics were measured before and after 8 weeks of aerobic training (3-4 times per week) in eight hypertensive (47 ± 2 years) and eight normotensive untrained individuals (46 ± 1 years) during arterial tyramine infusion, arterial ATP infusion and/or one-legged knee extensions. Before training, exercise hyperaemia and leg vascular conductance (LVC) were lower in the hypertensive individuals (P < 0.05) and tyramine lowered exercise hyperaemia and LVC in both groups (P < 0.05). Training lowered blood pressure in the hypertensive individuals (P < 0.05) and exercise hyperaemia was similar to the normotensive individuals in the trained state. After training, tyramine did not reduce exercise hyperaemia or LVC in either group. When tyramine was infused at rest, the reduction in blood flow and LVC was similar between groups, but exercise training lowered the magnitude of the reduction in blood flow and LVC (P < 0.05). There was no difference in the vasodilatory response to infused ATP or in muscle P2Y2 receptor content between the groups before and after training. However, training lowered the vasodilatory response to ATP and increased skeletal muscle P2Y2 receptor content in both groups (P < 0.05). These results demonstrate that exercise training improves functional sympatholysis and reduces postjunctional α-adrenergic responsiveness in both normo- and hypertensive individuals. The ability for functional sympatholysis and the vasodilator and sympatholytic effect of intravascular ATP appear not to be altered in essential hypertension.
authors.affiliation: Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark smortensen@health.sdu.dk.
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Mortensen
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Nyberg
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Lasse
authors.initials: L
authors.lastname: Gliemann
authors.affiliation: Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Pia
authors.initials: P
authors.lastname: Thaning
authors.affiliation: Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Bengt
authors.initials: B
authors.lastname: Saltin
authors.affiliation: Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Ylva
authors.initials: Y
authors.lastname: Hellsten
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007866:Leg / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism; D058474:Receptors, Purinergic P2X1 / Q000378:metabolism; D058473:Receptors, Purinergic P2Y2 / Q000378:metabolism; D013566:Sympathomimetics / Q000494:pharmacology; D014439:Tyramine / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D018759:Adrenergic Uptake Inhibitors; D058474:Receptors, Purinergic P2X1; D058473:Receptors, Purinergic P2Y2; D013566:Sympathomimetics; D014665:Vasodilator Agents; D000255:Adenosine Triphosphate; D014439:Tyramine