从牛尾状核分离的突触小泡组分对二价阳离子、ATP 依赖的[3H]亮氨酸脑啡肽的摄取

Divalent cation, ATP-dependent [3H]leu-enkephalin uptake by synaptic vesicle fraction isolated from bovine caudate nucleus.

作者信息

Takeda M, Takeda F, Matsumoto F, Tanaka R, Konno K

出版信息

Brain Res. 1982 Feb 25;234(2):319-26. doi: 10.1016/0006-8993(82)90872-1.

Abstract

The mechanism of [3H]Leu-enkephalin uptake into synaptic vesicle fraction from bovine caudate nucleus was investigated. The simultaneous addition of 2 mM MgCl2, 2 mM CaCl2, and 2 mM ATP stimulated the uptake 22 times over the control, whereas the separate addition of these agents augmented the uptake 2.4 times at most. The addition of 2 mM MGCl2 plus 2 mM ATP and of 2 mM CaCl2 plus 2 mM ATP increased the uptake 6.6 times and 4.5 times, respectively. The cation, ATP-dependent uptake reached its half-maximal level within 10 min after the initiation of incubation at 25 degrees C, and little Leu-enkephalin was taken up at 0 degree C. The apparent Km for the uptake of [3H]Leu-enkephalin was 1.8 x 10(-7) M. Guanosine triphosphate stimulated the uptake as well as ATP, whereas CTP and ITP were only one-fourth effective of ATP. The cation, ATP-dependent uptake was inhibited by 25% and 20% in the presence of 0.1 mM colchicine and 1 microM reserpine, respectively.

摘要

研究了[3H]亮氨酸脑啡肽从牛尾状核摄取到突触小泡组分中的机制。同时添加2 mM氯化镁、2 mM氯化钙和2 mM三磷酸腺苷（ATP）可使摄取量比对照增加22倍，而单独添加这些试剂最多可使摄取量增加2.4倍。添加2 mM氯化镁加2 mM ATP和2 mM氯化钙加2 mM ATP分别使摄取量增加6.6倍和4.5倍。阳离子依赖性的ATP摄取在25℃孵育开始后10分钟内达到其最大摄取量的一半，在0℃时几乎没有亮氨酸脑啡肽被摄取。[3H]亮氨酸脑啡肽摄取的表观米氏常数（Km）为1.8×10⁻⁷ M。三磷酸鸟苷（GTP）与ATP一样刺激摄取，而三磷酸胞苷（CTP）和三磷酸肌苷（ITP）的刺激效果仅为ATP的四分之一。在存在0.1 mM秋水仙碱和1 μM利血平的情况下，阳离子依赖性的ATP摄取分别被抑制25%和20%。