Intense exercise training induces adaptation in expression and responsiveness of cardiac β-adrenoceptors in diabetic rats

• Main Authors: Zouhal Hassane, Carré François, Delamarche Paul, Morel Sophie, Zguira Mohamed, Vincent Sophie, Malardé Ludivine, Gratas-Delamarche Arlette, Lahaye Solène, Bekono Françoise
• Format: Article
• Language: English
• Published: BMC 2010-11-01
• Series: Cardiovascular Diabetology
• Online Access: http://www.cardiab.com/content/9/1/72

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>This intense exercise training amplified the <it>in vivo </it>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.</p> <p>Conclusions</p> <p>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.</p>