Diverse effects of voluntary wheel running on tonic and agonist-induced NO action in rat forelimb and hindlimb skeletal muscle arteriesстатьяТезисы
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Дата последнего поиска статьи во внешних источниках: 14 августа 2017 г.
Аннотация:Introduction: Exercise training is known to increase NO-mediated vasodilatation in response to agonists and shear stress. Along with that, endothelium may continually produce NO in the absence of external stimulation. The alterations of such tonic NO secretion after exercise training are poorly understood. Therefore, we investigated the effects of voluntary wheel training on tonic and agonist-induced NO action in small skeletal muscle arteries of forelimb and hindlimb.
Methods: Six-week-old male Wistar rats were divided into sedentary and trained groups, the latter had 24-h access to running wheels. Eight weeks later the branches of a. profunda brachii and a. suralis were isolated and studied using wire myography. Tonic and agonist-induced NO modes of action were assessed by the effects of NOS inhibitor (L-NNA, 0.1 mM) on the contractile responses to methoxamine (alpha1-adrenoceptor agonist) and on the relaxant responses to acetylcholine, respectively.
Results: L-NNA significantly increased responses to methoxamine of forelimb and hindlimb arteries in sedentary, but not in trained rats. The effects of L-NNA on acetylcholine-induced relaxation of hindlimb arteries were similar in two groups, whereas in forelimb arteries NO-component of the response to acetylcholine was increased in trained vs. sedentary rats.
Conclusions: Voluntary wheel running eliminated tonic NO action in skeletal muscle arteries; this may augment constriction of these arteries at rest and their dilation during exercise. More prominent effect of exercise on agonist-induced NO action in forelimbs than in hindlimbs is probably due to stronger recruitment of forelimb muscles during wheel running