DIRECT PATCH RECORDING FROM IDENTIFIED PRESYNAPTIC TERMINALS MEDIATING GLUTAMATERGIC EPSCS IN THE RAT CNS, IN-VITRO
DIRECT PATCH RECORDING FROM IDENTIFIED PRESYNAPTIC TERMINALS MEDIATING GLUTAMATERGIC EPSCS IN THE RAT CNS, IN-VITRO
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DOI：
10.1113/jphysiol.1994.sp020303
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发表时间：
1994-09-15
影响因子：
5.5
通讯作者：
FORSYTHE, ID
中科院分区：
文献类型：
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作者：
FORSYTHE, ID
1. 上橄榄复合体的体外脑干切片制备已经被开发出来，允许从突触前末端（Held的花萼）和它的突触后靶点（梯形体内侧核的主神经元）进行贴片记录。采用DiI荧光染色法（1,1′-二十二烷基-3,3,3′，3′-四甲基多碳氰高氯酸盐）对固定组织进行染色，活体切片采用Lucifer黄染色，鉴定包膜单个MNTB神经元体的钙萼。来自MNTB神经元的全细胞记录显示，诱发的EPSCs之前有一个与突触前动作电位（AP）相对应的预峰。在某些情况下，一个移液管同时记录了突触前和突触后的成分，但在另外11个情况下，使用含有Lucifer Yellow的移液管获得了突触前记录的确认。在电流箝位下，突触前和突触后位点可以通过它们对阶跃去极化的响应来区分；突触前末端产生频率高达200 Hz的AP序列，而MNTB神经元产生单个AP。每个突触前AP的后超极化持续时间小于2 ms。在电压箝位下，突触前末端的阶跃去极化产生河豚毒素敏感的内向电流，随后迅速激活电位大于-60 mV的外向钾电流。向外电流在150 ms的步骤中几乎没有失活，4-氨基吡啶（200 μ M）在0 mV时阻断了持续电流的63.0 +/- 14.5%（平均+/- sd， n = 3）。就像乌贼的巨突触一样，哺乳动物的末端也能快速表达激活的“延迟整流器”型钾电流。
1. An in vitro brainstem slice preparation of the superior olivary complex has been developed permitting patch recording from a presynaptic terminal (calyx of Held) and from its postsynaptic target - the principal neurone of the medial nucleus of the trapezoid body (MNTB).2. The fluorescent stain DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) was used in fixed tissue and Lucifer Yellow in living slices, to identify calices enclosing single MNTB neuronal somata.3. Whole-cell recording from the MNTB neurone shows evoked EPSCs preceded by a prespike, corresponding to the presynaptic action potential (AP). In some cases one patch pipette recorded from both pre- and postsynaptic elements, but confirmation of exclusively presynaptic recording was obtained using pipettes containing Lucifer Yellow in a further eleven cases.4. Under current clamp, the pre- and postsynaptic sites could be distinguished by their response to step depolarizations; presynaptic terminals generated a train of APs at frequencies up to 200 Hz, while MNTB neurones gave a single AP. Each presynaptic AP had an after-hyperpolarization lasting less than 2 ms.5. Under voltage clamp, step depolarizations of presynaptic terminals generated a tetrodotoxin-sensitive inward current followed by rapidly activating outward potassium currents at potentials more positive than -60 mV. The outward current exhibited little inactivation over the 150 ms steps and 4-aminopyridine (200 mu M) blocked 63.0 +/- 14.5% (mean +/- S.D., n = 3) of the sustained current at 0 mV. Like the squid giant synapse, mammalian terminals express rapidly activating 'delayed rectifier'-type potassium currents.