Figure 6.

ATP induces muscle hypertrophy and alleviates muscle atrophy in an [Ca²⁺]_i- and mTOR-dependent manner. (A) Effects of ATP with or without BAPTA-AM or rapamycin on the increase of muscle weight in soleus, plantaris and gastrocnemius muscles (n = 4). (B) The cross-sectional area distributions were plotted as frequency histograms. At least 2800 fibers from 4 different soleus muscles were counted. (C) Expression of P2Y₁ and P2Y₂ receptor mRNA in soleus and plantaris muscle (n = 8). (D) Effects of ATP on soleus and gastrocnemius muscles weights in hindlimb-suspended (left) or denervated (right) muscle shown as a percentage of the control group (n > 4). * p < 0.05, ** p < 0.01 by ANOVA with Tukey-Kramer test in (A), and ** p < 0.01 by Student’s t-test in (D). Error bars indicate S.E.M.