Arachidonic Acid Activates Release of Calcium Ions from Reticulum via Ryanodine Receptor Channels in C2C12 Skeletal Myotubes

---

E. R. Muslikhov, I. F. Sukhanova, and P. V. Avdonin^*

Koltsov Institute of Developmental Biology, Russian Academy of Sciences, ul. Vavilova 26, 119334 Moscow, Russia; E-mail: pvavdonin@yandex.ru; eldr87@gmail.com; Irina131280@yandex.ru; idbras@bk.ru

^* To whom correspondence should be addressed.

Received December 4, 2013; Revision received January 15, 2014

---

Arachidonic acid causes an increase in free cytoplasmic calcium concentration ([Ca²⁺]_i) in differentiated skeletal multinucleated myotubes C2C12 and does not induce calcium response in C2C12 myoblasts. The same reaction of myotubes to arachidonic acid is observed in Ca²⁺-free medium. This indicates that arachidonic acid induces release of calcium ions from intracellular stores. The blocker of ryanodine receptor channels of sarcoplasmic reticulum dantrolene (20 µM) inhibits this effect by 68.7 ± 6.3% (p < 0.001). The inhibitor of two-pore calcium channels of endolysosomal vesicles trans-NED19 (10 µM) decreases the response to arachidonic acid by 35.8 ± 5.4% (p < 0.05). The phospholipase C inhibitor U73122 (10 µM) has no effect. These data indicate the involvement of ryanodine receptor calcium channels of sarcoplasmic reticulum in [Ca²⁺]_i elevation in skeletal myotubes caused by arachidonic acid and possible participation of two-pore calcium channels from endolysosomal vesicles in this process.

---

KEY WORDS: calcium ions, skeletal myotubes, arachidonic acid, ryanodine-sensitive channels

DOI: 10.1134/S0006297914050071

---