Belgum J H, Dvorak D R, McReynolds J S
J Physiol. 1983 Jul;340:599-610. doi: 10.1113/jphysiol.1983.sp014782.
Synaptic inputs to on-off ganglion cells in mudpuppy retina were studied by measuring current-voltage relations in darkness, during different phases of the response to light, and in the presence of 4 mM-Co2+. The addition of Co2+ to the bathing medium usually caused a hyperpolarization of the membrane potential in darkness and an increase in input resistance, indicating that on-off ganglion cells receive tonic excitatory synaptic input in darkness. Other results suggest that an additional synaptic input, with a reversal potential near the dark potential, may also be active in darkness. At the onset of a light stimulus in the receptive field centre all on-off ganglion cells responded with transient excitatory and inhibitory synaptic events, both of which were due to increases in conductance. Similar transient excitatory and inhibitory events occurred at the termination of the light stimulus. In about one-half of the on-off ganglion cells studied the synaptic activity during steady illumination was the same as in darkness. In the remaining cells steady illumination caused an increase in sustained inhibition.
通过测量在黑暗中、对光响应的不同阶段以及存在4 mM - Co²⁺时的电流 - 电压关系，研究了泥螈视网膜中开 - 关神经节细胞的突触输入。向浴液中添加Co²⁺通常会在黑暗中导致膜电位超极化并增加输入电阻，这表明开 - 关神经节细胞在黑暗中接受紧张性兴奋性突触输入。其他结果表明，在黑暗中可能还有一个额外的突触输入，其反转电位接近暗电位，也处于活跃状态。在感受野中心的光刺激开始时，所有开 - 关神经节细胞都以短暂的兴奋性和抑制性突触事件做出反应，这两者都是由于电导增加所致。在光刺激终止时也会发生类似的短暂兴奋性和抑制性事件。在大约一半被研究的开 - 关神经节细胞中，持续光照期间的突触活动与黑暗中相同。在其余细胞中，持续光照会导致持续抑制增加。
