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Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model
Published on: June 18, 2013
Choline transport in human placental brush-border membrane vesicles
1Department of Pharmacology, State University of New York, Health Science Center at Syracuse 13210.
Biochimica Et Biophysica Acta
|August 24, 1994
Summary
Human placental epithelial cells transport choline via a conductive pathway, not Na+-choline cotransport or H+ exchange. This pathway is inhibited by certain pharmaceuticals, suggesting potential interactions during placental drug transfer.
Area of Science:
- Biochemistry
- Physiology
- Pharmacology
Background:
- Choline is essential for fetal development and placental function.
- Understanding placental choline transport is crucial for fetal health and drug delivery.
- Existing knowledge on specific placental choline transport mechanisms is limited.
Purpose of the Study:
- To investigate choline transport pathways in human placental epithelia.
- To identify the specific mechanisms involved in choline uptake across the brush border membrane.
- To assess the interaction of choline transport with common pharmaceuticals.
Main Methods:
- Isolation of human placental brush border membrane vesicles.
- Tracer flux measurements using [3H]choline.
- Assessment of transport under varying ionic gradients (Na+, H+, K+) and pH.
- Inhibition studies with hemicholinium-3 and various pharmaceuticals.
Main Results:
- Absence of Na+-choline cotransport and choline/H+ exchange mechanisms.
- Identification of a conductive choline uptake pathway.
- Demonstration of mediated transport characteristics including saturation kinetics and counterflow.
- Inhibition of conductive choline uptake by several common pharmaceuticals.
Conclusions:
- Human placental epithelia utilize a conductive, mediated transport system for choline uptake.
- This pathway is distinct from Na+-choline cotransport and organic cation/H+ exchange.
- Several pharmaceuticals interact with this conductive choline transporter, impacting placental choline uptake.
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