Götz T, Kraushaar U, Geiger J, Lübke J, Berger T, Jonas P
Physiologisches Institut der Universität Freiburg, 79104 Freiburg, Germany.
J Neurosci. 1997 Jan 1;17(1):204-15. doi: 10.1523/JNEUROSCI.17-01-00204.1997.
AMPA- and NMDA-type glutamate receptors (AMPARs and NMDARs) mediate excitatory synaptic transmission in the basal ganglia and may contribute to excitotoxic injury. We investigated the functional properties of AMPARs and NMDARs expressed by six main types of basal ganglia neurons in acute rat brain slices (principal neurons and cholinergic interneurons of striatum, GABAergic and dopaminergic neurons of substantia nigra, globus pallidus neurons, and subthalamic nucleus neurons) using fast application of glutamate to nucleated and outside-out membrane patches. AMPARs in different types of basal ganglia neurons were functionally distinct. Those expressed in striatal principal neurons exhibited the slowest gating (desensitization time constant tau = 11.5 msec, 1 mM glutamate, 22 degrees C), whereas those in striatal cholinergic interneurons showed the fastest gating (desensitization time constant tau = 3.6 msec). The lowest Ca2+ permeability of AMPARs was observed in nigral dopaminergic neurons (PCa/PNa = 0.10), whereas the highest Ca2+ permeability was found in subthalamic nucleus neurons (PCa/PNa = 1.17). NMDARs of different types of basal ganglia neurons were less variable in their functional properties; those expressed in nigral dopaminergic neurons exhibited the slowest gating (deactivation time constant of predominant fast component tau1 = 150 msec, 100 microM glutamate), and those of globus pallidus neurons showed the fastest gating (tau1 = 67 msec). The Mg2+ block of NMDARs was similar; the average chord conductance ratio g-60mV/g+40mV was 0.18-0.22 in 100 microM external Mg2+. Hence, AMPARs expressed in different types of basal ganglia neurons are markedly diverse, whereas NMDARs are less variable in functional properties that are relevant for excitatory synaptic transmission and neuronal vulnerability.
AMPA 型和 NMDA 型谷氨酸受体（AMPARs 和 NMDARs）介导基底神经节中的兴奋性突触传递，并可能导致兴奋性毒性损伤。我们使用快速向有核和外向膜片钳施加谷氨酸的方法，研究了急性大鼠脑片中六种主要类型基底神经节神经元（纹状体的主要神经元和胆碱能中间神经元、黑质的 GABA 能和多巴胺能神经元、苍白球神经元以及丘脑底核神经元）所表达的 AMPARs 和 NMDARs 的功能特性。不同类型基底神经节神经元中的 AMPARs 在功能上是不同的。纹状体主要神经元中表达的 AMPARs 门控最慢（脱敏时间常数 τ = 11.5 毫秒，1 mM 谷氨酸，22℃），而纹状体胆碱能中间神经元中的 AMPARs 门控最快（脱敏时间常数 τ = 3.6 毫秒）。在黑质多巴胺能神经元中观察到 AMPARs 的 Ca2+ 通透性最低（PCa/PNa = 0.10），而在丘脑底核神经元中 Ca2+ 通透性最高（PCa/PNa = 1.17）。不同类型基底神经节神经元的 NMDARs 在功能特性上变化较小；黑质多巴胺能神经元中表达的 NMDARs 门控最慢（主要快速成分的失活时间常数 τ1 = 150 毫秒，100 μM 谷氨酸），而苍白球神经元的 NMDARs 门控最快（τ1 = 67 毫秒）。NMDARs 的 Mg2+ 阻断作用相似；在 100 μM 外部 Mg2+ 存在时，平均弦电导比 g-60mV/g+40mV 为 0.18 - 0.22。因此，不同类型基底神经节神经元中表达的 AMPARs 明显不同，而 NMDARs 在与兴奋性突触传递和神经元易损性相关的功能特性上变化较小。
