TABLE 5.

Uptake of naloxone and naltrexone into transport-expressing and control cells

Transporter	Compound	Concentration	Inhibitor	Incubation Time	Cleared Volumea		Test/Control Ratio
					Control Cells	Plus Transporter
		µM		min	µl/mg protein	µl/mg protein
OCT1	Naloxone	1	—	10	31.4 ± 0.4	28.7 ± 1.8	0.9
	Naltrexone	1	—	10	65.7 ± 3.8	70.3 ± 6.6	1.1
	[14C]Metformin	10	—	5	0.94 ± 0.113	13.1 ± 0.2	13.9
	[14C]Metformin	10	100 µM quinidine	5	0.158 ± 0.023	0.609 ± 0.001	3.9
OCT2	Naloxone	1	—	10	37.1 ± 4.7	37.3 ± 6.2	1.0
	Naltrexone	1	—	10	78.0 ± 11.3	71.0 ± 6.4	0.9
	[14C]Metformin	10	—	2	0.609 ± 0.080	46.4 ± 0.2	76.2
	[14C]Metformin	10	300 µM quinidine	2	0.240 ± 0.031	0.652 ± 0.225	2.7
OCT3	Naloxone	1	—	20	30.6 ± 4.2	35.9 ± 2.5	1.2
	Naltrexone	1	—	20	88.9 ± 7.5	80.2 ± 5.9	0.9
	[14C]TEA	5	—	20	3.29 ± 0.31	20.9 ± 0.6	6.4
	[14C]TEA	5	100 µM verapamil	20	0.946 ± 0.143	1.22 ± 0.32	1.3
OCTN1	Naloxone	1	—	10	197 ± 4	134 ± 25	0.7
	Naltrexone	1	—	10	179 ± 24	190 ± 56	1.1
	[14C]TEA	5	—	5	0.998 ± 0.259	12.1 ± 1.4	12.1
	[14C]TEA	5	100 µM verapamil	5	0.579 ± 0.148	0.877 ± 0.228	1.5
OCTN2	Naloxone	1	—	10	179 ± 16	161 ± 6	0.9
	Naltrexone	1	—	10	209 ± 19	209 ± 46	1.0
	[3H]Carnitine	0.03	—	2	1.32 ± 0.04	99.5 ± 3.8	75.4
	[3H]Carnitine	0.03	30 µM verapamil	2	0.953 ± 0.109	31.4 ± 2.2	32.9

TEA, triethylamine.

^aN = 3, Mean ± S.D.

—, inhibitor was not added to the incubation.