Pivovarov A S, Drozdova E I, Moskvitin A A
M. V. Lomonosov Moscow State University.
Neurosci Behav Physiol. 2001 Jan-Feb;31(1):55-60. doi: 10.1023/a:1026674214042.
Changes in excitatory postsynaptic currents (EPSC) and influx currents induced by local iontophoretic application of acetylcholine (ACh currents) to the surfaces of the bodies of identified neurons LPa3 and RPa3 in the common snail after heteroreceptor tetanic stimulation were studied. The effects of rhythmic application of acetylcholine (0.5-1.0 times per sec for 10-40 sec) on the magnitude of EPSC were analyzed, along with the effects of tetanic stimulation of the nerves (n. intestinalis, n. pallialis dexter, n. pallialis sinister; 1-5 Hz for 1-2 min) on the amplitudes of the ACh current and the magnitudes of EPSC evoked by stimulation of another nerve. The following changes in conditioning responses were found over 1-1.5 h after tetanization: rhythmic application of ACh to the dorsal surface of the cell body resulted in potentiation of EPSC, and tetanic orthodromic stimulation potentiated the ACh current and induced heterosynaptic depression of EPSC. These post-tetanic changes were not local--they developed in those chemoreceptor zones of the membrane which were not activated by the preceding conditioning rhythmic stimulation. It is concluded that generalized post-tetanic changes in neuron responses are induced by activation of its subsynaptic and extrasynaptic mediator chemoreceptors.
研究了在普通蜗牛中，对已鉴定的神经元LPa3和RPa3的胞体表面进行局部离子电渗法施加乙酰胆碱（ACh电流）后，兴奋性突触后电流（EPSC）和流入电流的变化，该变化是在异受体强直刺激之后发生的。分析了有节奏地施加乙酰胆碱（每秒0.5 - 1.0次，持续10 - 40秒）对EPSC大小的影响，以及对神经（肠神经、右侧外套神经、左侧外套神经；1 - 5赫兹，持续1 - 2分钟）进行强直刺激对ACh电流幅度和由另一神经刺激诱发的EPSC大小的影响。在强直刺激后1 - 1.5小时内发现了以下条件反应变化：有节奏地向细胞体背表面施加ACh导致EPSC增强，强直顺向刺激增强了ACh电流并诱导了EPSC的异突触抑制。这些强直后变化并非局部性的——它们在膜的那些化学感受器区域中发生，而这些区域并未被先前的条件性有节奏刺激所激活。得出的结论是，神经元反应的全身性强直后变化是由其突触下和突触外介质化学感受器的激活所诱导的。
