Publications

• Differential pharmacological in vitro properties of organic cation transporters and regional distribution in rat brain.

  Amphoux A., Vialou V., Drescher E., Bruess M., Mannoury La Cour C., Rochat C., Millan M.J., Giros B., Boenisch H., Gautron S.

  Organic cation transporters (OCTs) are polyspecific carriers implicated in low-affinity, corticosteroid-sensitive extraneuronal catecholamine uptake in peripheral tissues. The three main OCT subtypes, OCT1, OCT2 and OCT3, are also present in the brain, but their central role remains unclear. In th ... >> More

  Organic cation transporters (OCTs) are polyspecific carriers implicated in low-affinity, corticosteroid-sensitive extraneuronal catecholamine uptake in peripheral tissues. The three main OCT subtypes, OCT1, OCT2 and OCT3, are also present in the brain, but their central role remains unclear. In the present study, we investigated by comparative in situ hybridization analysis the regional distribution of these transporters in rat brain and compared their functional properties in stably transfected HEK293 cells expressing human or rat OCTs. In rat brain, OCT2 and OCT3 mRNAs are expressed predominantly in regions located at the brain-cerebrospinal fluid border, with OCT3 mRNA expression extending to regions that belong to monoaminergic pathways such as raphe nuclei, striatum and thalamus. After normalization with MPP+ uptake, OCT2 and OCT3 subtypes share a similar monoamine preference profile, with higher transport efficacies for epinephrine and histamine than for the other monoamines. Interestingly, a significant level of epinephrine transport, previously only shown for rOCT2, is achieved by most OCTs subtypes. Finally, another novel finding was that OCTs are sensitive to 3,4-methylenedioxymetamphetamine (MDMA), phencyclidine (PCP), MK-801 and ketamine. Altogether, all our results suggest a functional specialization of OCT subtypes, based both on their intrinsic properties and their differential regional expression pattern in the brain. << Less

  Neuropharmacology 50:941-952(2006) [PubMed] [EuropePMC]

  This publication is cited by 4 other entries.

• Interaction of cations, anions, and weak base quinine with rat renal cation transporter rOCT2 compared with rOCT1.

  Arndt P., Volk C., Gorboulev V., Budiman T., Popp C., Ulzheimer-Teuber I., Akhoundova A., Koppatz S., Bamberg E., Nagel G., Koepsell H.

  The rat organic cation transporter (rOCT)-2 was characterized by electrical and tracer flux measurements compared with rOCT1. By applying choline gradients to voltage-clamped Xenopus oocytes expressing rOCT2, potential-dependent currents could be induced in both directions. Tracer flux measurement ... >> More

  The rat organic cation transporter (rOCT)-2 was characterized by electrical and tracer flux measurements compared with rOCT1. By applying choline gradients to voltage-clamped Xenopus oocytes expressing rOCT2, potential-dependent currents could be induced in both directions. Tracer flux measurements with seven organic cations revealed similar Michaelis-Menten constant values for both transporters, with the exception of guanidine. In parallel experiments with rOCT2 and rOCT1, inhibition of tetraethylammonium transport by 12 cations, 2 weak bases, corticosterone, and the anions para-amminohippurate, alpha-ketoglutarate, and probenecid was characterized. The IC(50) values of many inhibitors were similar for both transporters, whereas others were significantly different. Mepiperphenidol and O-methylisoprenaline showed an approximately 70-fold lower and corticosterone a 38-fold higher affinity for rOCT2. With the use of these inhibitors together with previous information on cation transporters, experimental protocols are proposed to dissect out the individual contributions of rOCT2 and rOCT1 in intact proximal tubule preparations. Inhibition experiments at different pH levels strongly suggest that the weak base quinine passively permeates the plasma membrane at physiological pH and inhibits rOCT2 from the intracellular side. << Less

  Am. J. Physiol. 281:F454-F468(2001) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.