TABLE 1

K_{p brain} of 11 P-gp substrates in wild-type and mdr1a/1b(−/−) mice, and the observed K_{p brain} ratios

Quinidine, loperamide, digoxin, dexamethasone, and vinblastine were infused via jugular vein for 100 min at a dose rate of 838, 264, 197, 135, and 346 nmol · h⁻¹ · kg⁻¹ after rapid intravenous infusion for 1 min at a dose rate of 692, 201, 473, 1216, and 1248 nmol · min⁻¹ · kg⁻¹, respectively (n = 4–5). The brain-to-plasma concentration ratios (K_{p brain}) were measured at 100 min. The K_{p brain} ratios were obtained by dividing the K_{p brain} in mdr1a/1b(−/−) mice by that in wild-type mice. Each value represents the mean ± S.E.M., with the exception of loratadine. The S.E.M. was calculated according to the law of propagation of error.