ELECTRICAL ACTIVITY OF AMPHIBIAN LYMPH HEART
ELECTRICAL ACTIVITY OF AMPHIBIAN LYMPH HEART
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DOI：
10.1002/jcp.1030570106
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发表时间：
1961-01-01
影响因子：
--
通讯作者：
SANCHEZ, V
中科院分区：
文献类型：
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作者：
DELCASTILLO, J;SANCHEZ, V
两栖动物淋巴心脏的电活动已被检查使用外部电极和细胞内微量移液器。动作电流的爆发被认为是与每个收缩期。如果记录电极也应用于XI脊神经，则在每个肌肉动作电流之前观察到运动脉冲的齐射。对淋巴心脏运动轴突的刺激表明，收缩期放电是由5至10个双相动作电流的总和引起的，每个动作电流都是由一系列神经冲动引起的。淋巴心肌纤维的静息电位可能高达60 mV（细胞内为负），尽管记录的值通常较低，可能是由于细胞损伤。用细胞内微电极记录的收缩期放电类似于它们的细胞外对应物，由一些部分添加的快速去极化组成，每个幅度高达20 mV，随后是膜超极化的缓慢阶段。这些变化可能是胆碱能机制产生的突触后电位。淋巴心脏收缩机制的激活似乎是由突触去极化直接引起的，而不需要动作电位的干预。由此可以得出结论，淋巴心肌纤维类似于两栖类中形成所谓的“慢肌系统”的纤维。
The electrical activity of the amphibian lymph heart has been examined using both external electrodes and intracellular micropipettes. Bursts of action currents are seen to be associated with each systole. If recording electrodes are also applied to the XI spinal nerve volleys of motor impulses are observed preceding each muscle action current. Stimulation of the lymph cardiac motor axons shows that the systolic discharges arise by the summation of 5 to 10 diphasic action currents, each of them elicited by a volley of nerve impulses. The resting potential of lymph heart muscle fibres may be as high as 60 mV (cell inside negative), although recorded values are usually, lower due presumably to cell damage. The systolic discharges recorded with intracellular microelectrodes resemble their extracellular counterpart, consisting of a number of partially added fast depolarizations, up to 20 mV in amplitude each, followed by a slow phase of membrane hyperpolarization. These changes may be regarded as postsynaptic potentials produced by cholinergic mechanism. Activation of the contractile machinery of the lymph heart seems to be elicited directly by synaptic depolarization without the intervention of action potentials. It may be concluded that the lymph heart muscle fibres are similar to those forming the so-called "slow muscle system" in the Amphibia.