{'fraction_non_alphanumeric': 0.041463414634146344, 'fraction_numerical': 0.022764227642276424, 'mean_word_length': 6.034285714285715, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effects of ATP and adenosine on contraction amplitude of rat soleus muscle at different temperatures

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