Video Experimental Relacionado
Updated: Jun 29, 2026
28:13
Catheter Ablation in Combination With Left Atrial Appendage Closure for Atrial Fibrillation
Published on: February 26, 2013
Una mutación puntual del alfa 2-adrenoceptor que bloquea el acoplamiento a las corrientes de potasio pero no de
A Surprenant1, D A Horstman, H Akbarali
1Vollum Institute, Oregon Health Sciences University, Portland 97201.
Science (New York, N.Y.)
|August 14, 1992
Resumen
La mutación del receptor alfa 2A-adrenérgico impide la activación de las corrientes de potasio, lo que sugiere distintas vías de la proteína G para diferentes respuestas celulares. Esto impacta la comprensión de la señalización de los receptores acoplados a proteínas G.
Área de la Ciencia:
- Farmacología Farmacología.
- Biología Molecular Biología Molecular
- La neurociencia es la neurociencia.
Sus antecedentes:
- Los receptores alfa 2A-adrenérgicos son receptores acoplados a proteínas G involucrados en varias vías de señalización celular.
- Estos receptores modulan funciones como la actividad de la adenilil ciclasa, las corrientes de calcio y potasio.
Objetivo del estudio:
- Para investigar el papel de un residuo de ácido aspártico conservado (Asp79) en la señalización del receptor alfa 2A-adrenérgico.
- Para determinar si las proteínas G específicas median los efectos del receptor en diferentes canales iónicos.
Principales métodos:
- Expresión estable de los receptores alfa 2A-adrenérgicos de tipo salvaje y mutantes en las células tumorales de la hipófisis de ratón AtT20.
- Ensayos para medir la actividad de la adenilil ciclasa y las corrientes de los canales iónicos (calcio y potasio) en respuesta a los agonistas de los receptores.
Principales resultados:
- Los agonistas inhiben las corrientes de adenilil ciclasa y calcio en las células que expresan receptores de tipo salvaje y mutantes.
- Los agonistas aumentaron las corrientes de potasio que rectifican hacia adentro solo en células con el receptor de tipo salvaje.
- La mutación Asp79Asn abolió la potenciación de las corrientes de potasio.
Conclusiones:
- Los hallazgos sugieren que distintas proteínas G acoplan los receptores alfa 2A-adrenérgicos a los canales de potasio y calcio.
- El mutante alfa 2-adrenoceptor puede no ser capaz de adoptar la conformación necesaria para activar las proteínas G que controlan los canales de potasio.
Videos de Conceptos Relacionados
01:10Electrical Current
Electrical current is defined as the rate at which charge flows. When there is a large current present, such as that used to run a refrigerator, a large amount of charge moves through the wire in a small amount of time. If the current is small, such as that used to operate a handheld calculator, a small amount of charge moves through the circuit over a long period of time. The SI unit for current is the ampere (A), named for the French physicist André-Marie Ampère (1775–1836). An ampere is the...
01:13Magnetic Force Between Two Parallel Currents
Two long, straight, and parallel current-carrying conductors exert a force of equal magnitude on one another. The direction of the force depends on the current direction in the conductors.
The force exerted by the magnetic field due to the first conductor over a finite length of the second conductor is given as the product of the current in the second conductor and the vector product of the length vector along the current element and the field due to the first conductor. According to the...
The force exerted by the magnetic field due to the first conductor over a finite length of the second conductor is given as the product of the current in the second conductor and the vector product of the length vector along the current element and the field due to the first conductor. According to the...
01:21DC Battery
A conductor needs to be a component of a path that creates a closed loop or full circuit to have a continuous current flowing through it. A current starts to flow if an electric field is created inside an isolated conductor that is not part of a full circuit. The conductor quickly develops a net positive charge at one end and a net negative charge at the other. These charges generate an electric field opposite the direction of the applied electric field, which reduces the current. Eventually,...
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...
01:29Neuromuscular Junction And Blockade
The site of chemical communication between a motor neuron and a muscle fiber is called the neuromuscular junction (NMJ). The end of the motor neuron at the NMJ divides into a cluster of synaptic end bulbs. The cytoplasm of these bulbs consists of synaptic vesicles enclosing acetylcholine molecules, the principal neurotransmitter released at the NMJ. The region opposite the synaptic bulb that ends in the muscle fiber is called the motor end plate, which has acetylcholine receptors. Within the...
01:30Antihypertensive Drugs: Angiotensin II Receptor Blockers
In the renin-angiotensin-aldosterone system, a hormone called angiotensin II plays a crucial role. It binds to the AT1 receptors in vascular smooth muscles coupled with Gq proteins. The activation of these receptors activates an enzyme called phospholipase C, which releases two molecules: inositol trisphosphate and diacylglycerol. These molecules cause a chain reaction that leads to the phosphorylation of myosin light chains and promotes interaction between actin and myosin, leading to smooth...