Jacocks H M, Izenwasser S, Werling L L, Cox B M
Department of Pharmacology, Uniformed Services University, Bethesda, MD 20814-4799.
Life Sci. 1991;49(7):481-8. doi: 10.1016/0024-3205(91)90064-i.
Cocaine inhibits tritium-labeled dopamine ([3H]DA) uptake in rat (IC50 approximately 400 nM) and sheep (IC50 approximately 1 microM) striatum. GBR 12909, a selective DA uptake inhibitor, potently inhibits [3H]DA uptake in rat (IC50 less than 10 nM), but is less effective (only 60% of the uptake is inhibited at a concentration of 10 microM) and less potent (IC50 approximately 300 nM) in sheep. [3H]DA release from slices of rat or sheep striatum is stimulated by potassium (15-50 mM). In the presence of nomifensine (10 microM), cocaine (10 microM) had no effect on potassium-stimulated [3H]DA release in either species. [3H]DA release is increased by N-methyl-D-aspartate (NMDA) (10-1000 microM) in rat striatum but NMDA did not stimulate [3H]DA release in sheep striatum. These findings suggest that NMDA receptors either are absent from or do not regulate release of preloaded [3H]DA in sheep striatum.
可卡因抑制大鼠（IC50约为400 nM）和绵羊（IC50约为1 μM）纹状体中氚标记多巴胺（[3H]DA）的摄取。GBR 12909是一种选择性DA摄取抑制剂，能有效抑制大鼠纹状体中[3H]DA的摄取（IC50小于10 nM），但在绵羊中效果较差（在10 μM浓度下仅60%的摄取被抑制）且效力较低（IC50约为300 nM）。大鼠或绵羊纹状体切片中[3H]DA的释放受到钾（15 - 50 mM）的刺激。在诺米芬辛（10 μM）存在的情况下，可卡因（10 μM）对两种动物的钾刺激的[3H]DA释放均无影响。N - 甲基 - D - 天冬氨酸（NMDA）（10 - 1000 μM）可增加大鼠纹状体中[3H]DA的释放，但NMDA不能刺激绵羊纹状体中[3H]DA的释放。这些发现表明，NMDA受体在绵羊纹状体中要么不存在，要么不调节预加载的[3H]DA的释放。
