Lazaroff M, Dunlap K, Chikaraishi D M
Neuroscience Program, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
J Membr Biol. 1996 Jun;151(3):279-91. doi: 10.1007/s002329900078.
CATH.a is a central nervous system (CNS) catecholaminergic cell line derived from a transgenic mouse carrying the SV40 T antigen oncogene under the transcriptional control of regulatory elements from the rat tyrosine hydroxylase gene (Suri et al., 1993). CATH.a cells express several differentiated neuronal characteristics including medium and light chain neurofilament proteins, synaptophysin, tyrosine hydroxylase, and dopamine beta-hydroxylase; they synthesize dopamine and norepinephrine. Conversely, they do not express glial-specific fibrillary acidic protein. To establish definitively that CATH.a cells are of neuronal origin, we characterized the repertoire of voltage-gated inward currents expressed by CATH.a cells. Such inward currents are necessary for neuronal excitability. We report that all CATH.a cells possess a tetrodotoxin-sensitive sodium current (peak amplitude = 590 +/- 319 pA) and 68% possess a high voltage-activated calcium current (peak amplitude = 175 +/- 67 pA). Pharmacological analyses suggest that individual cells express varying levels of L- and N-type calcium current, but no P-type current. In addition, in 55% of the cells with a calcium current, about a half of this current is resistant to selective antagonists for L- and N-type currents, suggesting that another calcium current exists in these CATH.a cells which is not L-, N-, or P-type. The heterogeneous pattern of current detected persisted in several CATH. a subclones, suggesting that factors other than genetic variability influence current expression. The demonstration that CATH.a cells express these currents indicates that they have excitable membrane properties characteristic of neurons. Although many peripheral nervous system (PNS) cell lines exist, very few CNS cell lines with differentiated neuronal properties exist. Since the CATH.a cells can be grown continuously in large amounts, they may be useful for purifying, characterizing, and/or cloning various neuronal-specific molecules and thereby may add to our understanding of CNS catecholaminergic neurons.
CATH.a是一种中枢神经系统（CNS）儿茶酚胺能细胞系，源自一只转基因小鼠，该小鼠携带在大鼠酪氨酸羟化酶基因调控元件转录控制下的SV40 T抗原癌基因（苏里等人，1993年）。CATH.a细胞表达多种分化的神经元特征，包括中链和轻链神经丝蛋白、突触素、酪氨酸羟化酶和多巴胺β-羟化酶；它们合成多巴胺和去甲肾上腺素。相反，它们不表达胶质细胞特异性纤维酸性蛋白。为了明确确定CATH.a细胞起源于神经元，我们对CATH.a细胞表达的电压门控内向电流谱进行了表征。这种内向电流对于神经元的兴奋性是必需的。我们报告称，所有CATH.a细胞都具有河豚毒素敏感的钠电流（峰值幅度 = 590 ± 319 pA），68%的细胞具有高电压激活的钙电流（峰值幅度 = 175 ± 67 pA）。药理学分析表明，单个细胞表达不同水平的L型和N型钙电流，但没有P型电流。此外，在55%有钙电流的细胞中，约一半的这种电流对L型和N型电流的选择性拮抗剂有抗性，这表明这些CATH.a细胞中存在另一种不是L型、N型或P型的钙电流。在几个CATH.a亚克隆中检测到的电流异质性模式持续存在，这表明除了遗传变异性之外的因素会影响电流表达。CATH.a细胞表达这些电流的证明表明它们具有神经元特有的可兴奋膜特性。虽然存在许多外周神经系统（PNS）细胞系，但具有分化神经元特性的中枢神经系统细胞系却很少。由于CATH.a细胞可以大量连续培养，它们可能有助于纯化、表征和/或克隆各种神经元特异性分子，从而可能增进我们对中枢神经系统儿茶酚胺能神经元的理解。
