Papke R L, Bencherif M, Lippiello P
Department of Pharmacology and Therapeutics, University of Florida, Gainesville 32610-0267, USA.
Neurosci Lett. 1996 Aug 9;213(3):201-4. doi: 10.1016/0304-3940(96)12889-5.
The agonist properties of acetylcholine (ACh), tetramethylammonium, ethyl-trimethylammonium and choline were evaluated for muscle and neuronal nicotinic receptors in Xenopus oocytes. The only essential feature for a neuronal receptor agonist appears to be the charged nitrogen. For specific receptor subtypes, other structural elements appear permissive (neither increasing nor decreasing activity) or non-permissive (decreasing activity). Choline was a full agonist for alpha 7, but a hydroxyl group was strongly non-permissive for other receptor subtypes (alpha 1 beta 1 gamma delta, alpha 3 beta 4, alpha 3 beta 2, and alpha 4 beta 2). The binding of these ligands to brain membranes is consistent with the electrophysiological results. Physiological concentrations of choline desensitize alpha 7 receptors to ACh suggesting that, in vivo, choline may regulate both the activation and inactivation of this receptor.
在非洲爪蟾卵母细胞中评估了乙酰胆碱（ACh）、四甲铵、乙基三甲基铵和胆碱对肌肉和神经元烟碱样受体的激动剂特性。对于神经元受体激动剂而言，唯一的基本特征似乎是带电荷的氮。对于特定的受体亚型，其他结构元件似乎是允许的（既不增加也不降低活性）或不允许的（降低活性）。胆碱是α7的完全激动剂，但羟基对其他受体亚型（α1β1γδ、α3β4、α3β2和α4β2）具有强烈的非允许性。这些配体与脑膜的结合与电生理结果一致。胆碱的生理浓度会使α7受体对ACh脱敏，这表明在体内，胆碱可能调节该受体的激活和失活。
