In an experiment the transport of the neurotransmitter serotonin into cultured mammalian cells was measured. Batches of cells were incubated with solutions of different concentrations of radiolabelled [3H]-serotonin for a defined time, cells were then separated from the incubation buffer, and serotonin accumulated into the cells was determined by scintillation counting. The rate of transport is given as dpm/min* (see table below). In order to elucidate the transport mechanism, the experiment was conducted under two different conditions, i.e., in condition A normal transport buffer was used, and in condition B the transport buffer did not contain any Na* ions. [Notes: * dpm/min means disintegrations per minute and is a measure of the intensity of radioactivity of a radiolabelled compound; it is directly related to the rate of transport for this compound] serotonin [µM] 0.025 transport rate A [dpm/min] 300.0 transport rate B [dpm/min] 10 0.08 920.0 30.0 0.25 2500.0 100.0 0.7 5400.0 350.0 2 8800.0 1100.0 6. 9100.0 3000.0

In an experiment the transport of the neurotransmitter serotonin into cultured mammalian cells was measured. Batches of cells were incubated with solutions of different concentrations of radiolabelled [3H]-serotonin for a defined time, cells were then separated from the incubation buffer, and serotonin accumulated into the cells was determined by scintillation counting. The rate of transport is given as dpm/min* (see table below). In order to elucidate the transport mechanism, the experiment was conducted under two different conditions, i.e., in condition A normal transport buffer was used, and in condition B the transport buffer did not contain any Na* ions. [Notes: * dpm/min means disintegrations per minute and is a measure of the intensity of radioactivity of a radiolabelled compound; it is directly related to the rate of transport for this compound] serotonin [µM] 0.025 transport rate A [dpm/min] 300.0 transport rate B [dpm/min] 10 0.08 920.0 30.0 0.25 2500.0 100.0 0.7 5400.0 350.0 2 8800.0 1100.0 6. 9100.0 3000.0

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter3: The Plasma Membrane And Membrane Potential

Section: Chapter Questions

Problem 2SQE: One of the important uses of the Nernst equation is in describing the flow of ions across plasma...

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Describe the contribution of each of the following to establishing and maintaining membrane potential: (a) the Na+K+ pump, (b) passive movement of K+ across the membrane, (c) passive movement of Na+ across the membrane, and (d) the large intracellular anions.
A common membrane-bound intermediary between the receptor and the effector protein within the plasma membrane is the __________________.
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