Video Experimental Relacionado
Updated: Aug 11, 2026
12:48
Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays
Published on: February 19, 2013
Acceso extracelular a la bomba Na,K: vía similar a la del canal iónico
D C Gadsby1, R F Rakowski, P De Weer
1Marine Biological Laboratory, Woods Hole, MA 02543.
Science (New York, N.Y.)
|April 2, 1993
Resumen
La bomba de sodio y potasio es una bomba de sodio y potasio.
Área de la Ciencia:
- La biofísica es la biofísica.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La Na,K-ATPasa (bomba de sodio-potasio) es crucial para mantener los gradientes de iones celulares.
- Transporta tres iones de sodio hacia fuera y dos iones de potasio en cada ciclo.
- El movimiento de la carga durante el transporte iónico está relacionado con los cambios en la conformación de la bomba.
Objetivo del estudio:
- Para investigar la naturaleza del movimiento de carga durante la translocación de iones de sodio por la Na,K-ATPasa.
- Para determinar la dependencia de voltaje de la liberación y reunión de iones de sodio.
- Para entender la analogía funcional entre la bomba y los canales iónicos.
Principales métodos:
- Utilizó axones gigantes de calamares dialisados internamente y sujetos a tensión. axones gigantes de calamar.
- Se midió el eflujo unidireccional de sodio-22 a través del intercambio Na-Na en ausencia de potasio.
- Centrado en la vía de translocación de sodio de la bomba.
Principales resultados:
- La actividad de la Na,K-ATPasa, aunque electroneutral, exhibió sensibilidad al voltaje.
- Los potenciales de membrana cada vez más negativos aceleraron la tasa de intercambio Na-Na.
- La tasa de cambio seguía una curva sigmoide de saturación con voltaje.
Conclusiones:
- La liberación externa de iones de sodio y la recombinación son los principales pasos para mover la carga.
- Los iones de sodio extracelulares acceden a los sitios de unión a través de un canal de alto campo dentro de la bomba.
- Una porción de la molécula Na,K-ATPasa funciona de manera análoga a un canal iónico.
Videos de Conceptos Relacionados
01:47Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they...
01:19Ion Channels
The movement of ions like sodium, potassium, and calcium into and out of the cell is essential to maintain the electrochemical gradient in living cells. The ion channels—a class of membrane transport proteins—help maintain this ionic gradient for the smooth functioning of physiological activities such as maintaining cell size and volume, conducting nerve impulses, and gas and nutrient exchange.
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
01:29Primary Active Transport
In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would not...
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
01:19The Role of Ion Channels in Neuronal Computation
A postsynaptic neuron usually receives numerous impulses from several other presynaptic neurons. The axon hillock of the postsynaptic neuron integrates all these signals and determines the likelihood of firing an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
01:24Non-gated Ion Channels
Ion channels are specialized proteins on the plasma membrane that allow charged ions to pass down their electrochemical gradient. Their main function is to maintain the membrane potential which is critical for cell viability. These channels are either gated or non-gated and can transport more than a thousand ions within milliseconds for the cellular event to occur.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.