Effect of clenbuterol on sarcoplasmic reticulum function in single skinned mammalian skeletal muscle fibers.
نویسندگان
چکیده
We examined the effect of the β2-agonist clenbuterol (50 μM) on depolarization-induced force responses and sarcoplasmic reticulum (SR) function in muscle fibers of the rat ( Rattus norvegicus; killed by halothane overdose) that had been mechanically skinned, rendering the β2-agonist pathway inoperable. Clenbuterol decreased the peak of depolarization-induced force responses in the extensor digitorum longus (EDL) and soleus fibers to 77.2 ± 9.0 and 55.6 ± 5.4%, respectively, of controls. The soleus fibers did not recover. Clenbuterol significantly and reversibly reduced SR Ca2+loading in EDL and soleus fibers to 81.5 ± 2.8 and 78.7 ± 4.0%, respectively, of controls. Clenbuterol also produced an ∼25% increase in passive leak of Ca2+ from the SR of the EDL and soleus fibers. These results indicate that clenbuterol has direct effects on fast- and slow-twitch skeletal muscle, in the absence of the β2-agonist pathway. The increased Ca2+ leak in the triad region may lead to excitation-contraction coupling damage in the soleus fibers and could also contribute to the anabolic effect of clenbuterol in vivo.
منابع مشابه
Effect of indomethacin on force responses and sarcoplasmic reticulum function in skinned skeletal muscle fibers and cytosolic [Ca ] in myotubes
Han, Renzhi, Takuya Suizu, Miranda D. Grounds, and Anthony J. Bakker. Effect of indomethacin on force responses and sarcoplasmic reticulum function in skinned skeletal muscle fibers and cytosolic [Ca2 ] in myotubes. Am J Physiol Cell Physiol 285: C881–C890, 2003. First published June 18, 2003; 10.1152/ajpcell.00063.2003.—In this study, the effects of phospholipase A2 (PLA2) inhibitors on excita...
متن کاملEffect of indomethacin on force responses and sarcoplasmic reticulum function in skinned skeletal muscle fibers and cytosolic [Ca2+] in myotubes.
In this study, the effects of phospholipase A2 (PLA2) inhibitors on excitation-contraction coupling (ECC) and sarcoplasmic reticulum (SR) function were examined in skinned extensor digitorum longus (EDL) muscle fibers of the rat. The nonspecific PLA2 inhibitor indomethacin (200 microM) significantly increased the peak (approximately 2-fold, P = 0.02) and the width (approximately 6-fold, P = 0.0...
متن کاملEffect of lactate on depolarization-induced Ca21 release in mechanically skinned skeletal muscle fibers
Dutka, T. L., and G. D. Lamb. Effect of lactate on depolarization-induced Ca21 release in mechanically skinned skeletal muscle fibers. Am. J. Physiol. Cell Physiol. 278: C517–C525, 2000.—It is unclear whether accumulation of lactate in skeletal muscle fibers during intense activity contributes to muscle fatigue. Using mechanically skinned fibers from rat and toad muscle, we were able to examine...
متن کاملEffects of Chronic Administration of Clenbuterol on Contractile Properties and Calcium Homeostasis in Rat Extensor Digitorum Longus Muscle
Clenbuterol, a β2-agonist, induces skeletal muscle hypertrophy and a shift from slow-oxidative to fast-glycolytic muscle fiber type profile. However, the cellular mechanisms of the effects of chronic clenbuterol administration on skeletal muscle are not completely understood. As the intracellular Ca2+ concentration must be finely regulated in many cellular processes, the aim of this study was t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- American journal of physiology. Cell physiology
دوره 274 6 شماره
صفحات -
تاریخ انتشار 1998