Video Experimental Relacionado
Updated: Aug 16, 2026
10:19
Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes
Published on: January 11, 2011
La espermina y la espermidina como moléculas de entrada para los canales K+ del rectificador hacia adentro
E Ficker1, M Taglialatela, B A Wible
1Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030.
Science (New York, N.Y.)
|November 11, 1994
Resumen
Los canales K + del rectificador interno están bloqueados por Mg2 + intracelular y poliaminas como la espermina y la espermidina. Estas poliaminas pueden ser responsables del cerramiento intrínseco de los canales, influyendo en el flujo iónico.
Área de la Ciencia:
- La biofísica es la biofísica.
- Biología Molecular Biología Molecular
- Fisiología del canal iónico Fisiología del canal iónico
Sus antecedentes:
- Los canales K + del rectificador hacia adentro exhiben fuertes corrientes hacia adentro y corrientes hacia afuera bloqueadas.
- La rectificación hacia adentro se atribuye al bloqueo intracelular de Mg2+ y a un mecanismo de bloqueo intrínseco.
- La pérdida de las compuertas en los parches extirpados indica la participación de factores citoplasmáticos.
Objetivo del estudio:
- Investigar el papel de los factores citoplasmáticos en el cerramiento intrínseco de los canales K + del rectificador hacia adentro.
- Para identificar moléculas citoplasmáticas específicas responsables de la restauración de las puertas intrínsecas.
Principales métodos:
- Electrofisiología de la pinza de parche en parches de membrana extirpados.
- Aplicación de poliaminas (espermina, espermidina) a los parches extirpados.
- Análisis de la cinética de las compuertas de los canales y las relaciones corriente-voltaje.
Principales resultados:
- La puerta intrínseca se perdió en los parches extirpados, pero se pudo restaurar mediante concentraciones nanomolares de espermina y espermidina.
- Las poliaminas espermina y espermidina imitaban efectivamente los efectos de los factores citoplasmáticos endógenos.
- Los resultados sugieren que las poliaminas actúan como bloqueadores fisiológicos para los canales K + del rectificador hacia adentro.
Conclusiones:
- Es probable que la espermina y la espermidina sean bloqueadores fisiológicos de los canales K + del rectificador hacia adentro.
- El cerramiento "intrínseco" de estos canales puede resultar principalmente del bloqueo dependiente de la tensión por las poliaminas.
- Comprender las interacciones de la poliamina es crucial para comprender la función del canal K+.
Videos de Conceptos Relacionados
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.
01:19Ligand-gated Ion Channels
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
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.
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
01:19Ligand-gated Ion Channels
Ligand-gated ion channels are transmembrane proteins with a channel for ions to pass through and a binding site for a ligand. The channel opens only when a ligand attaches to the binding site.
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...