Intense exercise training induces adaptation in expression and responsiveness of cardiac β-adrenoceptors in diabetic rats.
BACKGROUND
Informations about the effects of intense exercise training on diabetes-induced myocardial dysfunctions are lacking. We have examined the effects of intense exercise training on the cardiac function of diabetic rats, especially focusing on the Langendorff β-adrenergic responsiveness and on the β-adrenoceptors protein expression.


METHODS
Control or Streptozotocin induced-diabetic male Wistar rats were randomly assigned to sedentary or trained groups. The training program consisted of 8 weeks running on a treadmill (10° incline, up to 25 m/min, 60 min/day) and was considered to be intense for diabetic rats.


RESULTS
This intense exercise training amplified the in vivo diabetes-induced bradycardia. It had no effect on Langendorff basal cardiac contraction and relaxation performances in control and diabetic rats. In diabetic rats, it accentuated the Langendorff reduced responsiveness to β-adrenergic stimulation. It did not blunt the diabetes-induced decrease of β1-adrenoceptors protein expression, displayed a significant decrease in the β2-adrenoceptors protein expression and normalized the β3-adrenoceptors protein expression.


CONCLUSIONS
Intense exercise training accentuated the decrease in the myocardial responsiveness to β-adrenergic stimulation induced by diabetes. This defect stems principally from the β2-adrenoceptors protein expression reduction. Thus, these results demonstrate that intense exercise training induces specific effects on the β-adrenergic system in diabetes.
Laboratory Movement Sport and health Sciences, UFR APS, University of Rennes 2, Rennes, France. soleneledouairon@gmail.com
Solène Le Douairon
Sle D
Lahaye
Arlette
A
Gratas-Delamarche
Ludivine
L
Malardé
Sophie
S
Vincent
Mohamed Sami
MS
Zguira
Sophie Lemoine
SL
Morel
Paul
P
Delamarche
Hassane
H
Zouhal
François
F
Carré
Françoise Rannou
FR
Bekono
D000222:Adaptation, Physiological; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D002950:Citrate (si)-Synthase / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D005082:Physical Exertion; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism; D022702:Receptors, Adrenergic, beta-3 / Q000378:metabolism; D012420:Running; D013997:Time Factors; D016277:Ventricular Function, Left
C547789:Adrb1 protein, rat; D000318:Adrenergic beta-Agonists; D011943:Receptors, Adrenergic, beta; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2; D022702:Receptors, Adrenergic, beta-3; D002950:Citrate (si)-Synthase; D007545:Isoproterenol