Video Experimental Relacionado
Updated: Aug 15, 2026
10:53
Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
El péptido atrionatriurético transforma los canales de sodio cardíacos en canales conductores de calcio
1Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085.
Science (New York, N.Y.)
|February 23, 1990
Resumen
El péptido atrionatriurético (ANP) suprime los canales cardíacos de sodio y calcio. Esta acción puede implicar la alteración del canal de sodio.
Área de la Ciencia:
- Fisiología cardiovascular fisiología cardiovascular.
- Cardiología Molecular Cardiología Molecular
- Función del canal iónico Función del canal iónico
Sus antecedentes:
- El péptido natriurético auricular (ANP) regula el volumen de líquido extracelular y la presión arterial.
- La ANP se libera de las células auriculares debido al aumento del volumen de líquido.
- Sus efectos conocidos incluyen una reducción de la absorción de sodio por los riñones.
Objetivo del estudio:
- Investigar los efectos directos de la ANP en los canales iónicos cardíacos.
- Para dilucidar el mecanismo por el cual la ANP influye en las corrientes de sodio y calcio en los miocitos ventriculares.
Principales métodos:
- Se realizaron grabaciones electrofisiológicas (patch-clamp) en miocitos ventriculares de ratas y conejillos de indias.
- Se midieron corrientes iónicas específicas (sodio y calcio) en presencia y ausencia de ANP.
Principales resultados:
- La ANP suprimió significativamente las corrientes de calcio y sodio en los miocitos ventriculares.
- La supresión de la corriente de sodio se relacionó con un aumento de la permeabilidad del canal al calcio, sin alterar la cinética o la sensibilidad a la tetrodotoxina.
- La modulación del canal inducida por ANP puede implicar cambios en el sitio de selectividad catiónica.
Conclusiones:
- La ANP tiene un impacto directo en la función de los canales iónicos cardíacos, suprimiendo específicamente las corrientes de sodio y calcio.
- El mecanismo implica una posible alteración de la selectividad del canal de sodio para los iones calcio.
- Esta supresión de las corrientes iónicas y la excitabilidad celular deprimida pueden contribuir a la regulación de la secreción de ANP.
Videos de Conceptos Relacionados
01:26Voltage-gated Ion Channels
Voltage-gated ion channels are transmembrane proteins that open and close in response to changes in the membrane potential. They are present on the membranes of all electrically excitable cells such as neurons, heart, and muscle cells.
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
01:12Mechanically-gated Ion Channels
Mechanically-gated ion channels are proteins found in eukaryotic and prokaryotic cell membranes that open in response to mechanical stress. Tension, compression, swelling, and shear stress can alter the conformation of the protein, opening a transmembrane channel that allows the passage of ions for signal transmission. In eukaryotes, mechanically-gated channels are distributed in several regions like the neurons, lungs, skin, bladder, and heart, where they play critical roles in numerous...
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,...
01:27Transducer Mechanism: Enzyme-Linked Receptors
Enzyme-linked receptors are cell-surface receptors acting as an enzyme or associating with an enzyme intracellularly. They make excellent drug targets. Drugs can bind to the extracellular ligand-binding domain or directly affect their enzymatic domain and alter their activity.
Major types that are helpful drug targets include:
Major types that are helpful drug targets include:
01:18Antihypertensive Drugs: Action of Calcium Channel Blockers
Calcium ions are essential to contract smooth muscle cells in blood vessels. They enter these cells through voltage-dependent calcium channels, specifically L-type calcium channels in the cell membrane. These L-type calcium channels are integral to the excitation-contraction coupling process in smooth muscle. When a stimulus is received by smooth muscle cells, their membrane depolarizes. This alteration in membrane potential instigates the opening of L-type calcium channels. As a result,...
01:30Cardiac Action Potential
Cardiac action potentials are essential for proper heart function, enabling the rhythmic contractions needed for adequate blood circulation. Nodal cells and Purkinje fibers, specialized for electrical conduction, generate these action potentials.
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials