Stetzer E, Ebbinghaus U, Storch A, Poteur L, Schrattenholz A, Kramer G, Methfessel C, Maelicke A
Laboratory of Molecular Neurobiology, Institute of Physiological Chemistry and Pathobiochemistry, Johannes-Gutenberg University Medical School, Mainz, Germany.
FEBS Lett. 1996 Nov 11;397(1):39-44. doi: 10.1016/s0014-5793(96)01115-5.
The alpha3/beta4 subtype of neuronal nicotinic acetylcholine receptor (nAChR) was stably expressed in human embryonic kidney (HEK) 293 cells that co-expressed a voltage-gated Ca2+ channel. alpha3/beta4-nAChR-expressing clones were identified using the fura-2 Ca2+ imaging technique, and were further characterised by single-cell and whole-cell patch-clamp studies. Acetylcholine (ACh) induced fast activating currents which showed desensitisation and inward rectification. The conductance of the ACh-activated channel was 29 pS. The order of potency of the nicotinic agonists tested was cytisine approximately = nicotine > acetylcholine. The EC50 value for ACh was 145 microM; the Hill coefficient was close to 2. The currents elicited by ACh were effectively blocked by nicotinic antagonists, but not by the muscarinic antagonist atropine. These properties are comparable to the pharmacological and physiological profile of ganglionic nicotinic receptors and type III currents of cultured hippocampal neurons.
神经元烟碱型乙酰胆碱受体（nAChR）的α3/β4亚型在共表达电压门控Ca2+通道的人胚肾（HEK）293细胞中稳定表达。使用fura-2 Ca2+成像技术鉴定表达α3/β4-nAChR的克隆，并通过单细胞和全细胞膜片钳研究进一步表征。乙酰胆碱（ACh）诱导快速激活电流，该电流表现出脱敏和内向整流。ACh激活通道的电导为29 pS。所测试的烟碱激动剂的效力顺序为金雀花碱≈尼古丁＞乙酰胆碱。ACh的EC50值为145 microM；希尔系数接近2。ACh引发的电流被烟碱拮抗剂有效阻断，但未被毒蕈碱拮抗剂阿托品阻断。这些特性与神经节烟碱受体的药理学和生理学特征以及培养的海马神经元的III型电流相当。
