Bryan L J, O'Donnell S R
Br J Pharmacol. 1984 Jul;82(3):757-62. doi: 10.1111/j.1476-5381.1984.tb10815.x.
The extraneuronal uptake of the (-)- and (+)-isomers of three catecholamines, isoprenaline, adrenaline and noradrenaline, were compared in guinea-pig trachealis smooth muscle cells, by a fluorescence microphotometric method. Preliminary experiments showed that the initial rates of uptake of the (-)-isomers were greater than those of the (+)-isomers in tissues incubated in 25 microM adrenaline or noradrenaline or 50 microM isoprenaline. More detailed experiments showed that the Km values of the (+)-isomers of the amines for extraneuronal uptake were not significantly different from each other, but the Km value of (-)-isoprenaline less than (-)-adrenaline less than (-)-noradrenaline. Thus, the order of the ratios of the Km values for the (+):(-)-isomers was isoprenaline greater than adrenaline greater than noradrenaline. The results showed that there is stereoselectivity of the extraneuronal uptake of catecholamines, but it is greatest for isoprenaline (4.9 fold), less for adrenaline (2.5 fold) and almost negligible (1.6 fold) for noradrenaline.
采用荧光显微光度法，比较了豚鼠气管平滑肌细胞对三种儿茶酚胺（异丙肾上腺素、肾上腺素和去甲肾上腺素）的（-）-和（+）-异构体的神经元外摄取情况。初步实验表明，在25微摩尔肾上腺素或去甲肾上腺素或50微摩尔异丙肾上腺素中孵育的组织中，（-）-异构体的初始摄取速率高于（+）-异构体。更详细的实验表明，胺类（+）-异构体的神经元外摄取的Km值彼此之间无显著差异，但（-）-异丙肾上腺素的Km值小于（-）-肾上腺素小于（-）-去甲肾上腺素。因此，（+）：（-）-异构体的Km值之比顺序为异丙肾上腺素大于肾上腺素大于去甲肾上腺素。结果表明，儿茶酚胺的神经元外摄取存在立体选择性，但对异丙肾上腺素最大（4.9倍），对肾上腺素较小（2.5倍），对去甲肾上腺素几乎可忽略不计（1.6倍）。
