carrier-mediated transport

carrier-mediated transport

The transport of a molecule from point A, usually on one side of a cell (e.g., external to the cell), to point B via a transmembrane carrier.

Properties
• Chemical specificity;
• Competitive Inhibition;
• Non-competitive inhibition.

carrier-mediated transport

movement which occurs across membranes, such as the blood-brain barrier and the gastrointestinal mucosa. Inherent in the mechanism is a rapidly reversible reaction between the substance being transported and components of the membrane. The membrane component is the 'carrier'. The mechanism is also characterized by (1) being saturable; (2) like substances being able to compete for the services of the carrier so that competitive inhibition occurs.
There are two forms of carrier-mediated transport, active transport and facilitated diffusion. The rapid transfer of drug metabolites into urine is by active transport. Entry of glucose into most cells is by facilitated diffusion but its passage across the gastrointestinal mucosa is by active transport. Active transport requires a direct expenditure of energy, whereas facilitated diffusion is not energy dependent. Active transport can move substances against a concentration gradient, facilitated diffusion cannot.
References in periodicals archive ?
The information derived from these studies will represent an important step forward toward a systematic characterization of the role of carrier-mediated transport in drug uptake.
More specifically, biogenic amines are transported through BBB by diffusion and it never occurs by carrier-mediated transport.
Further, metabolic fuels, monocarboxylic acids, ethanol, vitamins and neurotransmitters are carried by carrier-mediated transport because low lipid soluble biomolecules can traverse the blood brain barrier.
exchange across the blood brain barrier takes place by carrier-mediated transport [120], mainly by brain capillary [Na.
Carrier-mediated transport can also be divided into a number of different mechanisms dependent on energy and/or cotransport of another substance.
Physiological strategies are followed by applying endogenous transport mechanisms by using either carrier-mediated transport of nutrients or receptor-mediated transport of peptides.
Effect of grapefruit juice, naringin, naringenin, and bergamottin on the intestinal carrier-mediated transport of talinolol in rats.
In five chapters, the authors cover the thermodynamics of irreversible processes (including balance equations), transport equations (including the Fickian, Nernst-Planck and Stefan-Maxwell approaches), transport and electrodes (including electrode processes in stationery states, hydrodynamic electrodes, and non-stationary or transient electrode processes), transport in membranes (including neural porous membranes, Donnan equilibrium and steady-state transport) and transport through liquid membranes, particularly carrier-mediated transport.
Carrier-mediated transport of valproic acid in BeWo cells, a human trophoblast cell line.
Although Caco-2 cells originate from human colon carcinoma, they acquire many features of absorptive intestinal cells during culture such as microvillus structure, metabolic enzymes and carrier-mediated transport systems for sugars, amino acids and several drugs.

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