Nurse S, Lacaille J C
Département de physiologie, Faculté de médecine, Université de Montréal, QC, Canada.
Can J Physiol Pharmacol. 1997 May;75(5):520-5.
GABAergic inhibition of hippocampal pyramidal cells is mediated by two distinct subtypes of postsynaptic receptors, GABAA and GABAB. Electrical stimulation of inhibitory cells or fibres in the CA1 subfield of the hippocampus yields a biphasic inhibitory postsynaptic potential (IPSP) in pyramidal cells, consisting of an early GABAA- and a late GABAB-mediated component. CA1 interneurons are a heterogeneous population of cells, which differ on the basis of their morphology, physiological properties, target selectivity onto principal cells, and network connectivity. Inhibitory synaptic circuitry appears to be specialized, since feedback inhibition may invoke only postsynaptic GABAA receptors, whereas feedforward inhibition may invoke both postsynaptic GABAA and GABAB receptors. In this review, we examine the evidence for and against the notion that distinct interneurons may be responsible for GABAA- and GABAB-mediated inhibition. Overall, the evidence suggests that (i) certain interneurons may generate solely GABAA inhibition, but the available data do not distinguish whether other interneurons mediate (ii) solely GABAB inhibition or (iii) a combination of both GABAA and GABAB.
海马锥体细胞的γ-氨基丁酸（GABA）能抑制作用由两种不同的突触后受体亚型介导，即GABAA和GABAB。对海马CA1亚区的抑制性细胞或纤维进行电刺激，可在锥体细胞中产生双相抑制性突触后电位（IPSP），它由早期的GABAA介导成分和晚期的GABAB介导成分组成。CA1中间神经元是一类异质性细胞群体，它们在形态、生理特性、对主细胞的靶标选择性以及网络连接性方面存在差异。抑制性突触回路似乎具有特异性，因为反馈抑制可能仅激活突触后GABAA受体，而前馈抑制可能同时激活突触后GABAA和GABAB受体。在这篇综述中，我们审视了支持和反对不同中间神经元可能分别负责GABAA介导的抑制和GABAB介导的抑制这一观点的证据。总体而言，证据表明：（i）某些中间神经元可能仅产生GABAA抑制作用，但现有数据无法区分其他中间神经元是否介导（ii）仅GABAB抑制作用，或（iii）GABAA和GABAB的联合抑制作用。
