Demushkin V P, Kotelevtsev Iu V
Biokhimiia. 1980 Oct;45(10):1773-9.
A procedure of isolation of membrane-bound acetylcholine receptor from the optical ganglia of the squid Berryteuthis magister has been developed. The method described entails tissue disruption by homogenization and ultrasonication, resulting in a crude membrane fraction, and a subsequent washing of the membranes with 1 M NaCl and 0,6 M KCl, reaching the receptor yield of 250 pM per 1 g of tissue. Some properties of the receptor, which is of nicotinic type, were studied. The Kd values for the receptor complexes with acetylcholine (3 +/- 0,5 mkM), nicotine (1 +/- 0,2 mkM), tubocurarine (0,3 +/- 0,1; 4,4 +/- 0,5 mkM), cytisine (0,5 +/- 0,1 mkM), etc. were determined. The binding depends on pH and decreases with a decrease of pH, is inhibited by high concentrations of NaCl and weakly depends on the concentrations of Ca2+, Mg2+ and EDTA sodium salt. In contrast to the acetylcholine receptor of vertebrates, the receptor from the optical ganglia of B. magister is not blocked by decamethonium and alpha-neurotoxin II from the Middle Asian cobra N. naja oxiana venom, a close analog of alpha-bungarotoxin.
已开发出一种从大王乌贼（Berryteuthis magister）视神经节中分离膜结合型乙酰胆碱受体的方法。所述方法包括通过匀浆和超声处理破坏组织，得到粗膜部分，随后用1 M氯化钠和0.6 M氯化钾洗涤膜，每1克组织的受体产量达到250皮摩尔。对该烟碱型受体的一些特性进行了研究。测定了受体与乙酰胆碱（3±0.5微摩尔）、尼古丁（1±0.2微摩尔）、筒箭毒碱（0.3±0.1；4.4±0.5微摩尔）、金雀花碱（0.5±0.1微摩尔）等形成的复合物的解离常数（Kd值）。结合作用取决于pH值，随pH值降低而降低，受高浓度氯化钠抑制，且对钙离子、镁离子和乙二胺四乙酸钠盐的浓度依赖性较弱。与脊椎动物的乙酰胆碱受体不同，大王乌贼视神经节中的受体不会被十烃季铵以及来自中亚眼镜蛇（N. naja oxiana）毒液的α-神经毒素II（α-银环蛇毒素的类似物）阻断。
