【摘要】 目的探讨温度对心脏自律性的影响机制。方法心率变异性(HRV)功率谱分析、细胞内动作电位记录和放射免疫法测窦房结组织内环-磷酸腺苷(cAMP)含量。结果温度变化前后,人和家兔的LF/HF都没有显著差异;温度升高,可使窦房结细胞动作电位的4期自动除极速率加快,窦房结组织内的cAMP含量增加;在窦房结主要离子流If、Ik、ICa.T中,If对温度的变化最为敏感。结论温度对心率的影响并非通过神经因素,而是由温度对窦房结的直接作用所致,并且这一作用可能与cAMP对If电流的调控有关。更多还原

【Abstract】 AIM To study how temperature affects pacemaker activities of sinus-node cells.METHODS Heart rate variability（HRV） power spectrum analysis,action potential recording and radioimmunoassay were employed.RESULTS LF/HF had not changed significantly with different temperatures,while the higher temperature could both directly increase the spontaneous depolarization rate of SAN cells and the concentration of cAMP in the SAN preparations.Among the major pacemaker currents(I_f,I_K,I_Ca·T),I_f was the most sensitive one to the changes of temperature.CONCLUSION The changes of temperature directly act on SAN cells instead of via nervous mechanism,and intracellular cAMP may mediate this effect.更多还原