Hohage H, Stachon A, Feidt C, Hirsch J R, Schlatter E
Medizinische Poliklinik, Universität Münster, Germany.
J Pharmacol Exp Ther. 1998 Jul;286(1):305-10.
The regulation of transport of the fluorescent organic cation 4-(4-dimethylaminostyryl)-N-methylpyridinium (ASP+) by renal proximal tubular organic cation transport was studied in IHKE-1 and LLC-PK1 cells with a recently established fluorometric technique (Stachon et al., 1996, 1997). Stimulation of Ca++/diacylglycerol-dependent protein kinase by 1,2-dioctanoyl glycerol (DOG; 0.01-1 mumol/l, n = 7), ATP (0.1 mmol/l, n = 9), oxytocin (0.1 mumol/l, n = 6) and bradykinin (1 mumol/l, n = 7) resulted in an increase of ASP+ accumulation in IHKE-1 cells by 35 +/- 9% (DOG), 65 +/- 30% (ATP), 66 +/- 14% (bradykinin) and 70 +/- 20% (oxytocin) as compared with basal conditions, whereas ASP+ accumulation was slightly reduced in LLC-PK1 cells after stimulation with DOG (1 mumol/l, -20 +/- 7%, n = 10) and angiotensin II (0.1 nmol/l, -20 +/- 5%, n = 6). ASP+ accumulation in IHKE-1 cells also was increased by 0.5 mumol/l (20 +/- 8%, n = 8) and 1 mumol/l forskolin (35 +/- 13%, n = 19), and by 8-bromo-cAMP (1 mumol/l, 125 +/- 25%, n = 9), both activators of the cAMP-dependent protein kinase (PKA). Activation of the cGMP-dependent protein kinase (PKG) by human atrial natriuretic peptide (10 nmol/l, n = 10) or 8-bromo-cGMP (0.1 mmol/l, n = 12) resulted in an increase of 35 +/- 5% and 28 +/- 6%, respectively. Activation of PKA and PKG had no influence on ASP+ transport in LLC-PK1 cells. Regulation of ASP+ uptake by these two cell lines may be caused by direct phosphorylation of the organic cation transporters involved or by regulation of trafficking of the transporters to the membrane. Differences in the organic cation transporter isoforms or alternatively, in the trafficking may contribute to the distinct regulation of ASP+ transport in IHKE-1 and LLC-PK1 cells.
采用一种新建立的荧光测定技术（施塔洪等人，1996年、1997年），在IHKE - 1细胞和LLC - PK1细胞中研究了肾近端小管有机阳离子转运对荧光有机阳离子4 -（4 - 二甲基氨基苯乙烯基）- N - 甲基吡啶鎓（ASP +）转运的调节作用。用1,2 - 二辛酰甘油（DOG；0.01 - 1 μmol/L，n = 7）、ATP（0.1 mmol/L，n = 9）、催产素（0.1 μmol/L，n = 6）和缓激肽（1 μmol/L，n = 7）刺激Ca++/二酰基甘油依赖性蛋白激酶，与基础条件相比，导致IHKE - 1细胞中ASP +积累增加35±9%（DOG）、65±30%（ATP）、66±14%（缓激肽）和70±20%（催产素），而在用DOG（1 μmol/L，-20±7%，n = 10）和血管紧张素II（0.1 nmol/L，-20±5%，n = 6）刺激后，LLC - PK1细胞中ASP +积累略有减少。0.5 μmol/L（20±8%，n = 8）和1 μmol/L福斯可林（35±13%，n = 19）以及cAMP依赖性蛋白激酶（PKA）的两种激活剂8 - 溴 - cAMP（1 μmol/L，125±25%，n = 9）也使IHKE - 1细胞中的ASP +积累增加。人心房钠尿肽（10 nmol/L，n = 10）或8 - 溴 - cGMP（0.1 mmol/L，n = 12）激活cGMP依赖性蛋白激酶（PKG）分别导致增加35±5%和28±6%。PKA和PKG的激活对LLC - PK1细胞中的ASP +转运没有影响。这两种细胞系对ASP +摄取的调节可能是由于所涉及的有机阳离子转运体直接磷酸化或通过转运体向膜的转运调节引起的。有机阳离子转运体同工型的差异，或者转运的差异，可能导致IHKE - 1细胞和LLC - PK1细胞中ASP +转运的不同调节。
