A. E. Khairullin, S. Grishin, Azat I. Gabdrahmanov, A. U. Ziganshin
{"title":"ATP对正常和低温条件下大鼠慢速和快速骨骼肌收缩时间参数的影响","authors":"A. E. Khairullin, S. Grishin, Azat I. Gabdrahmanov, A. U. Ziganshin","doi":"10.3390/muscles2010003","DOIUrl":null,"url":null,"abstract":"We have previously shown that hypothermia leads to an increase in the synaptic modulating effects of ATP but not of adenosine in several different animal skeletal muscles. In this paper, we studied the effect of ATP on the amplitude–time parameters of single and tetanic contractions of rats’ isolated fast (1) and slow (2) muscles at different temperatures. We found that when muscles were stimulated by the electrical field (0.1 Hz, 0.5 ms, 10 V), with a decrease in the bath temperature from 37 °C to 14 °C (3), there was an increase in the half-relaxation time of the slow muscle (m. soleus), but not of the fast muscle (m. EDL). Similar effects were observed using a carbachol-induced contraction technique, which suggests the postsynaptic (4) nature of the expansion of the contractile response of the slow muscle induced by ATP (5). To confirm the postsynaptic nature of the observed phenomenon, experiments were performed at a high calcium level (7.2 mM), in which the presynaptic effects of ATP were shown to be offset. We found that the hypercalcium condition did not significantly change the effects of ATP on the measured parameters in both muscles. To record muscle tetanic contractions, we gradually increased the frequency of electrical impulses with the increment of 2.5 Hz to achieve the fusion frequencies of 12.5 Hz for m. soleus and 17.5 Hz for m. EDL at normal temperatures. ATP (100 μM) did not change the fusion frequency for both muscles at a normal temperature but decreased this parameter for the slow muscle to 5 Hz at 14 °C without affecting that for the fast muscle. We conclude that ATP potentiates a hypothermia-induced increase in the half-relaxation time of the contraction of rats’ slow, but not fast, skeletal muscles by acting on postsynaptic P2 receptors (6).","PeriodicalId":46318,"journal":{"name":"MLTJ-Muscles Ligaments and Tendons Journal","volume":"28 1","pages":""},"PeriodicalIF":0.5000,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Effects of ATP on Time Parameters of Contractility of Rats’ Slow and Fast Skeletal Muscles in Normal and Hypothermic Conditions\",\"authors\":\"A. E. Khairullin, S. Grishin, Azat I. Gabdrahmanov, A. U. Ziganshin\",\"doi\":\"10.3390/muscles2010003\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We have previously shown that hypothermia leads to an increase in the synaptic modulating effects of ATP but not of adenosine in several different animal skeletal muscles. In this paper, we studied the effect of ATP on the amplitude–time parameters of single and tetanic contractions of rats’ isolated fast (1) and slow (2) muscles at different temperatures. We found that when muscles were stimulated by the electrical field (0.1 Hz, 0.5 ms, 10 V), with a decrease in the bath temperature from 37 °C to 14 °C (3), there was an increase in the half-relaxation time of the slow muscle (m. soleus), but not of the fast muscle (m. EDL). Similar effects were observed using a carbachol-induced contraction technique, which suggests the postsynaptic (4) nature of the expansion of the contractile response of the slow muscle induced by ATP (5). To confirm the postsynaptic nature of the observed phenomenon, experiments were performed at a high calcium level (7.2 mM), in which the presynaptic effects of ATP were shown to be offset. We found that the hypercalcium condition did not significantly change the effects of ATP on the measured parameters in both muscles. To record muscle tetanic contractions, we gradually increased the frequency of electrical impulses with the increment of 2.5 Hz to achieve the fusion frequencies of 12.5 Hz for m. soleus and 17.5 Hz for m. EDL at normal temperatures. ATP (100 μM) did not change the fusion frequency for both muscles at a normal temperature but decreased this parameter for the slow muscle to 5 Hz at 14 °C without affecting that for the fast muscle. We conclude that ATP potentiates a hypothermia-induced increase in the half-relaxation time of the contraction of rats’ slow, but not fast, skeletal muscles by acting on postsynaptic P2 receptors (6).\",\"PeriodicalId\":46318,\"journal\":{\"name\":\"MLTJ-Muscles Ligaments and Tendons Journal\",\"volume\":\"28 1\",\"pages\":\"\"},\"PeriodicalIF\":0.5000,\"publicationDate\":\"2023-01-12\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"MLTJ-Muscles Ligaments and Tendons Journal\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.3390/muscles2010003\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"ORTHOPEDICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"MLTJ-Muscles Ligaments and Tendons Journal","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3390/muscles2010003","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ORTHOPEDICS","Score":null,"Total":0}
Effects of ATP on Time Parameters of Contractility of Rats’ Slow and Fast Skeletal Muscles in Normal and Hypothermic Conditions
We have previously shown that hypothermia leads to an increase in the synaptic modulating effects of ATP but not of adenosine in several different animal skeletal muscles. In this paper, we studied the effect of ATP on the amplitude–time parameters of single and tetanic contractions of rats’ isolated fast (1) and slow (2) muscles at different temperatures. We found that when muscles were stimulated by the electrical field (0.1 Hz, 0.5 ms, 10 V), with a decrease in the bath temperature from 37 °C to 14 °C (3), there was an increase in the half-relaxation time of the slow muscle (m. soleus), but not of the fast muscle (m. EDL). Similar effects were observed using a carbachol-induced contraction technique, which suggests the postsynaptic (4) nature of the expansion of the contractile response of the slow muscle induced by ATP (5). To confirm the postsynaptic nature of the observed phenomenon, experiments were performed at a high calcium level (7.2 mM), in which the presynaptic effects of ATP were shown to be offset. We found that the hypercalcium condition did not significantly change the effects of ATP on the measured parameters in both muscles. To record muscle tetanic contractions, we gradually increased the frequency of electrical impulses with the increment of 2.5 Hz to achieve the fusion frequencies of 12.5 Hz for m. soleus and 17.5 Hz for m. EDL at normal temperatures. ATP (100 μM) did not change the fusion frequency for both muscles at a normal temperature but decreased this parameter for the slow muscle to 5 Hz at 14 °C without affecting that for the fast muscle. We conclude that ATP potentiates a hypothermia-induced increase in the half-relaxation time of the contraction of rats’ slow, but not fast, skeletal muscles by acting on postsynaptic P2 receptors (6).
期刊介绍:
MLTJ (Muscle, Ligaments and Tendons Journal) is an open access, peer-reviewed online journal that encompasses all aspects of clinical and basic research studies related to musculoskeletal, ligament, tendon, public health, exercise physiology and kinesiology issues. Muscle, Ligaments and Tendons Journal (MLTJ) provides the platform for exchange of new clinical and scientific information in the most precise and expeditious way to achieve timely dissemination of information and cross-fertilization of ideas. It is the official journal of the Italian Society of Muscles, Ligaments and Tendons (I.S.Mu.L.T.), Società Italiana Terapia con Onde D’urto (S.I.T.O.D.) and Società Italiana Studio Piede e Caviglia (S.I.S.P.E.C)