Yanaura M, Nakashima M, Yamada S, Shiono S
Central Research Laboratory, Mitsubishi Electric Corporation, Hyogo, Japan.
Brain Res. 1993 Nov 26;629(1):88-94. doi: 10.1016/0006-8993(93)90485-6.
We have characterized the slow inhibitory synaptic connection between an left upper quadrant (LUQ) neuron and neuron L10, L12 or L13 in culture. A slow postsynaptic outward current in the LUQ neuron was elicited by repetitive firing of the co-cultured cholinergic neuron L10 as well as neuron L12 or L13 which were not cholinergic but FMRFamide synthesizing neurons. This outward current was due to an increase in K+ conductance and was relatively insensitive to external application of tetraethylammonium and 4-aminopyridine. We also investigated the effects of injection of a guanosine 5'-triphosphate (GTP) analogue into the LUQ neuron and extracellular application of serotonin and an adenosine 3',5'-cyclic monophosphate (cAMP) analogue on the current. In all the investigated properties, no significant difference was found among neuron L10, L12 and L13 as a presynaptic neuron. The slow postsynaptic current appeared to be virtually identical to the FMRFamide or acetylcholine (ACh)-induced K+ current reported in vivo, which resembled the 'S' current in Aplysia sensory neurons. We performed experiments to see the effect of phenyltrimethylammonium, an ACh antagonist, on the postsynaptic, ACh-, and FMRFamide-induced currents, clearly indicating that the neurotransmitter used in the cultured synapses was not ACh.
我们已经对培养物中左上象限（LUQ）神经元与神经元L10、L12或L13之间的缓慢抑制性突触连接进行了表征。共培养的胆碱能神经元L10以及非胆碱能但能合成FMRF酰胺的神经元L12或L13的重复放电可诱发LUQ神经元中缓慢的突触后外向电流。这种外向电流是由于钾离子电导增加所致，并且对外部施加的四乙铵和4-氨基吡啶相对不敏感。我们还研究了向LUQ神经元注射鸟苷5'-三磷酸（GTP）类似物以及细胞外应用5-羟色胺和腺苷3',5'-环磷酸（cAMP）类似物对该电流的影响。在所有研究的特性中，作为突触前神经元的L10、L12和L13神经元之间未发现显著差异。这种缓慢的突触后电流似乎与体内报道的FMRF酰胺或乙酰胆碱（ACh）诱导的钾电流几乎相同，类似于海兔感觉神经元中的“S”电流。我们进行了实验，观察ACh拮抗剂苯基三甲基铵对突触后、ACh和FMRF酰胺诱导电流的影响，清楚地表明培养突触中使用的神经递质不是ACh。
