海兔巨大神经元的电压钳制：早期钠电流和钙电流

Voltage clamp of the Aplysia giant neurone: early sodium and calcium currents.

Geduldig D, Gruener R

J Physiol. 1970 Nov;211(1):217-44. doi: 10.1113/jphysiol.1970.sp009276.

Abstract

The membrane properties of the Aplysia giant neurone were studied under controlled voltage conditions. Emphasis was placed on the early transient currents resulting from step polarizations applied while the ganglion was immersed in different test solutions.2. Early inward-going currents were observed when the neurone was bathed in normal saline (containing both Na and Ca), in Ca-free (Na-containing) saline, in Na-free (Ca-containing) saline, and in the normal saline to which tetrodotoxin 10(-5) g/ml. was added. When both Na and Ca are absent from the bathing solution no evidence for early inward-going current could be found.3. When tetrodotoxin is added to the normal saline, the maximum inward-going current is reduced, and no further reduction of this current is observed when the external Na-concentration is subsequently halved in the presence of the drug. When the external Ca-concentration is increased fivefold in the presence of the drug, the maximum transient current increases significantly.4. Hyperpolarizing prepulses result in a membrane inactivation in the presence of tetrodotoxin or in the absence of Na. In the presence of Na (and absence of tetrodotoxin) no such voltage-dependent inactivation occurs, and for this case, inactivation results only from depolarizing prepulses.

摘要

在可控电压条件下研究了海兔巨型神经元的膜特性。重点关注在神经节浸入不同测试溶液时施加阶跃极化所产生的早期瞬态电流。
当神经元浸浴在正常盐溶液（含有钠和钙）、无钙（含钠）盐溶液、无钠（含钙）盐溶液以及添加了10(-5)克/毫升河豚毒素的正常盐溶液中时，观察到早期内向电流。当浸浴溶液中同时没有钠和钙时，未发现早期内向电流的证据。
当向正常盐溶液中添加河豚毒素时，最大内向电流减小，并且在药物存在的情况下随后将外部钠浓度减半时，未观察到该电流的进一步减小。当在药物存在的情况下将外部钙浓度增加五倍时，最大瞬态电流显著增加。
在存在河豚毒素或无钠的情况下，超极化预脉冲会导致膜失活。在有钠（且无河豚毒素）的情况下，不会发生这种电压依赖性失活，对于这种情况，失活仅由去极化预脉冲引起。