2 TYPES OF NEURON IN THE RAT VENTRAL TEGMENTAL AREA AND THEIR SYNAPTIC INPUTS
2 TYPES OF NEURON IN THE RAT VENTRAL TEGMENTAL AREA AND THEIR SYNAPTIC INPUTS
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DOI：
10.1113/jphysiol.1992.sp019136
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发表时间：
1992-05-01
影响因子：
5.5
通讯作者：
NORTH, RA
中科院分区：
文献类型：
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作者：
JOHNSON, SW;NORTH, RA
1. 对大鼠中脑切片的241个腹侧被盖神经元进行了细胞内记录。77%的神经元被多巴胺极化（主细胞）；(2)被阿片肽（次级细胞）超极化。大多数主细胞自发放电（1-3 Hz），阈值为-53 mV；大多数次生细胞不能自发放电。主细胞的动作电位（0.9 ms）比次细胞的动作电位（0.5 ms）长。腹侧被盖区局部电刺激引起双相突触电位，先去极化后超极化，持续时间约200 ms。受体拮抗剂实验表明，去极化组分是由n-甲基- d -天冬氨酸（NMDA）和非NMDA受体的激活引起的，超极化组分是由GABA(A)受体的激活引起的。在50 ms的潜伏期后，出现了一个后期的超极化突触电位，在250 ms时达到峰值，持续时间约为1 s。它在-108 mV（外钾浓度2.5 mM）时极性反转，被苯氯芬（30-mu-M-1 mM）或2-羟氯芬（100-300-mu-M）阻断。在一些细胞中，一种抗苯氯芬成分仍然存在，这种成分被可卡因增加，并被舒必利（1 μ m）阻断。结果表明，腹侧被盖区含有两种性质与黑质相似的神经元。细胞接受由作用于NMDA和非NMDA受体的兴奋性氨基酸、作用于GABA(A)和GABA(B)受体的GABA以及作用于D2受体的多巴胺介导的突触输入。
1. Intracellular recordings were made from 241 ventral tegmental neurones in slices of rat midbrain. Seventy-seven per cent of neurones were hyperpolarized by dopamine (principal cells); 16% were hyperpolarized by opioid peptides (secondary cells).2. Most principal cells fired spontaneously (1-3 Hz) with a threshold of -53 mV; most secondary cells did not fire spontaneously. Action potentials of principal cells were longer (0.9 ms) than those of secondary cells (0.5 ms).3. Focal electrical stimulation within the ventral tegmental area evoked a biphasic synaptic potential, depolarization followed by hyperpolarization, with a duration of about 200 ms. Experiments with receptor antagonists showed that the depolarizing component resulted from activation of both N-methyl-D-aspartate (NMDA) and non-NMDA receptors and the hyperpolarizing component resulted from activation of GABA(A) receptors.4. A later hyperpolarizing synaptic potential developed after a latency of 50 ms, reached its peak in 250 ms and had a duration of about 1 s. It reversed polarity at -108 mV (external potassium concentration was 2.5 mM), was blocked by phaclofen (30-mu-M-1 mM) or 2-hydroxysaclofen (100-300-mu-M). In some cells, a phaclofen-resistant component remained that was increased by cocaine and blocked by sulpiride (1-mu-M).5. It is concluded that the ventral tegmental area contains two types of neurone having properties similar to those in the substantia nigra. The cells receive synaptic inputs mediated by excitatory amino acids acting at NMDA and non-NMDA receptors, GABA acting at GABA(A) and GABA(B) receptors, and dopamine acting at D2 receptors.