Effects of ATP and adenosine on contraction amplitude of rat soleus muscle at different temperatures. Issue 3 (1st October 2016) - Ziganshin, Ayrat U.
ABSTRACT: Introduction : The aim of this study was to evaluate the effects of adenosine 5′‐triphosphate (ATP) and adenosine on the contractility of mammalian skeletal muscle under hypothermic conditions. Methods : Contractions of isolated rat soleus muscle were induced by either electrical stimulation (ES) or carbachol at physiological temperatures (37°C) and hypothermic conditions (30–14°C) and recorded in the presence of ATP, adenosine, suramin, and 8‐(p‐sulfophenyl)‐theophylline (8‐SPT). Results : At 37°C, incubation of the muscles with ATP inhibited ES‐induced contractions; the inhibitory effect of ATP disappeared at 14°C. Adenosine inhibited ES‐induced contractions at all temperature levels; 8‐SPT fully prevented the action of adenosine. ATP and adenosine did not significantly affect carbachol‐induced contractions at 37°C, while at lower temperatures ATP potentiated them. Suramin fully prevented effects of ATP. Conclusions : ATP is involved in both pre‐ and postsynaptic regulation of rat soleus muscle contractility, and these processes are significantly more pronounced at low temperatures. Muscle Nerve 55 : 417–423, 2017