Koike K, Ohtsuki H, Takayanagi I
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Can J Physiol Pharmacol. 1990 Aug;68(8):1143-7. doi: 10.1139/y90-171.
The relationship between the sensitivity (the pD2 value) of carbachol and the density (the total concentration of receptors) of muscarinic receptors using single cells from the guinea pig taenia caecum prepared with a mixture of crude collagenase and trypsin inhibitor, purified collagenase alone, and a mixture of purified collagenase and papain was examined. The sensitivity of the single cells prepared with a mixture of purified collagenase and papain was about 10 times more effective than that of the single cells prepared under other conditions. The dissociation constant of [3H]quinuclidinyl benzilate (QNB) and Hill's coefficient did not change in the single cells prepared under the three conditions, though the maximum binding sites were significantly greater in the cells prepared with the mixture of purified collagenase and papain than in those prepared by other means. These results suggest that the increase in the sensitivity of carbachol obtained in the single cells prepared with this mixture is due to the increase in the density of muscarinic receptors and also suggest that the effects of this enzyme mixture may be due to an increase in the incorporation of newly synthesized receptors and (or) changes in receptor turnover.
使用粗制胶原酶和胰蛋白酶抑制剂的混合物、单独的纯化胶原酶以及纯化胶原酶和木瓜蛋白酶的混合物制备豚鼠盲肠带的单细胞，研究了卡巴胆碱的敏感性（pD2值）与毒蕈碱受体密度（受体总浓度）之间的关系。用纯化胶原酶和木瓜蛋白酶的混合物制备的单细胞的敏感性比在其他条件下制备的单细胞高约10倍。在三种条件下制备的单细胞中，[3H]喹核醇基苯甲酸酯（QNB）的解离常数和希尔系数没有变化，尽管用纯化胶原酶和木瓜蛋白酶的混合物制备的细胞中的最大结合位点比用其他方法制备的细胞中的最大结合位点显著更大。这些结果表明，用这种混合物制备的单细胞中卡巴胆碱敏感性的增加是由于毒蕈碱受体密度的增加，并且还表明这种酶混合物的作用可能是由于新合成受体掺入的增加和（或）受体周转的变化。
