| First Author | Zwart R | Year | 2001 |
| Journal | Mol Cell Biol | Volume | 21 |
| Issue | 13 | Pages | 4188-96 |
| PubMed ID | 11390648 | Mgi Jnum | J:69978 |
| Mgi Id | MGI:2135855 | Doi | 10.1128/MCB.21.13.4188-4196.2001 |
| Citation | Zwart R, et al. (2001) Impaired activity of the extraneuronal monoamine transporter system known as uptake-2 in Orct3/Slc22a3-deficient mice. Mol Cell Biol 21(13):4188-96 |
| abstractText | Two uptake systems that control the extracellular concentrations of released monoamine neurotransmitters such as noradrenaline and adrenaline have been described. Uptake-1 is present at presynaptic nerve endings, whereas uptake-2 is extraneuronal and has been identified in myocardium and vascular and nonvascular smooth muscle cells. The gene encoding the uptake-2 transporter has recently been identified in humans (EMT), rats (OCT3), and mice (Orct3/Slc22a3). To generate an in vivo model for uptake-2, we have inactivated the mouse Orct3 gene. Homozygous mutant mice are viable and fertile with no obvious physiological defect and also show no significant imbalance of noradrenaline or dopamine. However, Orct3-null mice show an impaired uptake-2 activity as measured by accumulation of intravenously administered [(3)H]MPP(+) (1-methyl-4-phenylpyridinium). A 72% reduction in MPP(+) levels was measured in hearts of both male and female Orct3 mutant mice. No significant differences between wild-type and mutant mice were found in any other adult organ or in plasma. When [(3)H]MPP(+) was injected into pregnant females, a threefold-reduced MPP(+) accumulation was observed in homozygous mutant embryos but not in their placentas or amniotic fluid. These data show that Orct3 is the principal component for uptake-2 function in the adult heart and identify the placenta as a novel site of action of uptake-2 that acts at the fetoplacental interface. |
