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为研究主动脉前庭自发慢反应电位的去极离子流性质 ,利用豚鼠的离体心脏 ,常规玻璃微电极细胞内记录方法和离子通道阻断剂 ,观测最大舒张电位 (MDP)、0相除极幅度 (APA)、0相最大除极速度 (Vmax)、4相自动除极速度 (VDD)、复极 5 0 % (APD50 )和 90 % (APD90 )的时间以及自发放电频率 (RPF)。结果发现 :(1) 0 5 μmol/L尼索地平 (Nis)可使该慢电位的APA、Vmax、VDD明显减小 ,RPF减慢 ,与给药前相比P <0 0 1;(2 ) 1 2mmol/L河豚毒 (TTX)使APA和Vmax与给药前相比有所减慢 (P <0 0 5 ) ,VDD和RPF明显减慢 (P <0 0 1) ;(3) 2mmol/L 4 氨基吡啶 (4 AP)使该慢电位的MDP的绝对值、APA、Vmax减小 ,VDD和RPF加快 ,与给药前相比有显著差异 (P <0 0 1) ;(4 ) 1 5mmol/LCsCl作用 5min时 ,VDD和RPF明显降低 (P <0 0 5 ) ,10min时恢复 ;(5 )无糖低氧液灌流 15min后 ,该慢电位VDD和RPF明显减慢 (P <0 0 1)。结果表明 :(1)该区域自发慢电位 0相的主要去极离子流除Ca2 +内流外 ,还可能有少量Na+内流。 (2 ) 4相去极离子流中 ,除Ca2 +、Na+的内流和IK 衰减外 ,If 电流可能也起部分作用。
In order to study the depolarizing ion current properties of spontaneous slow response potential in the aortic vestibule, the isolated rat heart, conventional glass microelectrode intracellular recording method and ion channel blocker were used to observe the maximal diastolic potential (MDP), phase 0 depolarization APA, Vmax, 4-phase automatic depolarization rate (VDD), 50% APD50 and 90% APD90, and spontaneous firing frequency (RPF). The results showed that: (1) 0 5 μmol / L nisoldipine significantly reduced APA, Vmax, VDD and slowed down RPF, P <0.01 compared with those before administration; ) 2 mmol / L tetrodotoxin (TTX) decreased APA and Vmax compared with that before administration (P <0.05), while VDD and RPF decreased significantly (P <0.01); (3) / L 4-aminopyridine (4 AP) decreased the absolute value of APP, APA, Vmax, VDD and RPF, and there was a significant difference (P <0.01) VDD and RPF were significantly decreased (P <0 05) at 5 min after 5 mmol / L LCsCl treatment, and restored at 10 min. (5) Slow VDD and RPF decreased significantly 0 1). The results showed that: (1) In addition to the influx of Ca2 +, the main depolarizing ion of spontaneous slow potential 0 phase in this region may also have a small amount of Na + influx. (2) In the 4-phase depolarized ion current, the If current may also play a part role, except for the influx of Ca2 + and Na + and the IK decay.