Cortical GABAergic Cell Subtypes and Their Synaptic Connections

体外研究了大鼠额叶皮质gaba能细胞的生理、形态、免疫组织化学和药理特性。(1)大gabaergybasket细胞的生理化学异质性。胆囊收缩素（CCK）细胞和小白蛋白细胞形成与其他细胞体相对立的钮扣。小白蛋白细胞属于快速尖峰细胞。相比之下，CCK细胞被发现是规则尖峰（RS）或突发尖峰（BS）非锥体（NP）细胞。大的生长抑素细胞属于RSNP类别，似乎不像大的CCK和小蛋白细胞那样频繁地与躯体对立。(2)皮质gaba能细胞亚型的选择性胆碱能调节。胆碱能或毒蕈碱激动剂确实通过刺激抑制性中间神经元在锥体细胞中诱导gaba能突触后电流。甲胆碱或肌碱对含肽gabaergy细胞的活性有明显影响，但对含小白蛋白的快穗型gabaergy细胞和晚穗型gabaergy细胞的活性无明显影响。生长抑素细胞或VIP细胞通过spike放电去极化。胆碱能激动剂对CCK细胞的影响呈异质性。较大的CCK细胞呈超极化后缓慢去极化，而较小的CCK细胞仅呈去极化。(3) gaba能细胞类型的去肾上腺素能激发和抑制。去甲肾上腺素（NA）和a-肾上腺素能激动剂、6 -氟肾上腺素（FNE）诱导锥体细胞IPSC频率增加，但b-肾上腺素能激动剂没有作用。河豚毒素、二胡碱和a-肾上腺素能拮抗剂降低了这种增加，这表明gaba能细胞是通过a-肾上腺素受体兴奋的。应用NA或FNE可使快速或晚穗细胞去极化，但没有细胞表现出穗放电。大多数生长抑素细胞去极化，并伴有尖刺放电。在少数情况下，这之前是超极化。胆囊收缩素细胞受到的影响是异质性的：去极化、超极化后再去极化或超极化。少

Cortical GABAergic Cell Subtypes and Their Synaptic ConnectionsPhysiological, morphological immunohistochemical and pharmacological characteristics of GABAergic cells in rat frontal cortex of rats were studied in vitro. (1) Physiological and chemical heterogeneity of large GABAergic basket cells. Cholecystokinin (CCK) cells and parvalbumin cells made boutons apposed to other cell bodies. Parvalbumin cells belonged to fast-spiking (FS) cells. In contrast, CCK cells were found to be regular-spiking (RS) or burst-spiking (BS) nonpyramidal (NP) cells. Large somatostatin cells belonged to the RSNP category which did not seem to be apposed to the somata so frequently as large CCK and parvalbumin cells. (2) Selective cholinergic modulation of cortical GABAergic cell subtypes. Cholinergic or muscarinic agonists indeed induced GABAergic postsynaptic currents in pyramidal cells by exciting inhibitory interneurons. Carbachol or muscarine affected the activities of peptide-containing GABAergic cel … More ls, but not of GABAergic cells of fast-spiking characteristics containing parvalbumin and GABAergic cells of late-spiking characteristics. Somatostatin or VIP cells were depolarized with spike firing. CCK cells were affected heterogeneously by cholinergic agonists. Larger CCK cells were hyperpolarized followed by a slow depolarization, whereas smaller CCK cells were only depolarized. (3) Noradrenergic excitation and inhibition of GABAergic cell types. Noradrenaline (NA) and an a-adrenergic agonist, 6 fluoronorepinephrine (FNE) induced an increase of IPSC frequency in pyramidal cells, but not a b-adrenergic agonist. This increase was reduced by tetrodotoxin, bicuculline and a-adrenergic antagonists, suggesting that GABAergic cells are excited via a-adrenoceptors. Fast spiking or late spiking cells were depolarized by application of NA or FNE, but none demonstrated spike firings. Most somatostatin cells were depolarized, accompanied by spike firing. In a few cases this was preceded by hyperpolarization. Cholecystokinin cells were affected heterogeneously: depolarization, hyperpolarization followed by depolarization, or hyperpolarization resulted. Less