Video Experimental Relacionado
Updated: Jul 6, 2026
11:57
Electroporation of Mycobacteria
Published on: May 23, 2008
La entrada de calcio conduce a la inactivación del canal de calcio en el Paramecio
Science (New York, N.Y.)
|December 15, 1978
Resumen
Los canales de calcio en el paramecio se inactivan rápidamente durante la despolarización. Esta inactivación es causada por la entrada de calcio y difiere de la inactivación del canal de sodio descrita por el modelo de Hodgkin-Huxley.
Área de la Ciencia:
- Electrofisiología celular La electrofisiología celular.
- Biofísica de los canales iónicos.
- Investigaciones sobre el paramecio.
Sus antecedentes:
- Las abrazaderas de tensión despolarizadoras revelan corrientes entrantes transitorias en el Paramecio.
- Comprender los mecanismos de la inactivación de los canales iónicos es crucial en la fisiología celular.
Objetivo del estudio:
- Para investigar el mecanismo de relajación de la corriente de calcio en Paramecium.
- Para determinar si la inactivación del canal de calcio es dependiente de la tensión o dependiente de la entrada.
Principales métodos:
- Análisis de la pinza de tensión en Paramecium.
- Sustitución del calcio extracelular por estroncio o bario.
- Análisis de las corrientes de calcio durante pulsos de despolarización.
Principales resultados:
- Una corriente de calcio hacia adentro se relajó rápidamente en 10 milisegundos.
- La relajación se ralentizó significativamente al reemplazar el calcio por estroncio o bario.
- La inactivación persistió después de un pulso, reduciendo las subsiguientes corrientes de calcio.
- La inactivación dependía de la entrada de calcio, no del potencial de la membrana.
Conclusiones:
- La inactivación de los canales de calcio en el paramecio es una consecuencia de la entrada de calcio durante la despolarización.
- Este mecanismo de inactivación difiere cualitativamente de la inactivación del canal de sodio en el modelo de Hodgkin-Huxley.
Videos de Conceptos Relacionados
01:19Contact-dependent Signaling
Contact-dependent signaling, as the name suggests, requires that communicating cells be in direct contact with each other. This is achieved either through receptor-ligand interactions or by specialized cytoplasmic channels that allow the flow of small molecules between cells. In animal cells, channels called gap junctions facilitate contact-dependent signaling in certain tissues, whereas, plasmodesmata perform a similar function in plants.
Gap Junctions
In animal cells, gap junctions are formed...
Gap Junctions
In animal cells, gap junctions are formed...
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...
01:24Non-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.
01:21G-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,...
01:27Diversity of Protists II
Alveolates are a group of organisms recognized by the presence of alveoli, which are cytoplasmic sacs located beneath the cell membrane. While their function remains uncertain, alveoli may help regulate water balance by controlling how much water enters and leaves the cell. In dinoflagellates, these structures may serve as armor plates. There are three major types of alveolates: ciliates, which move using cilia; dinoflagellates, which use flagella for movement; and apicomplexans, which are...
01:12Giardiasis
Giardiasis is a globally prevalent intestinal infection caused by the protozoan parasite Giardia duodenalis (also known as G. lamblia or G. intestinalis). This flagellated protozoan is the most frequently identified intestinal parasite in the United States and worldwide. Transmission primarily occurs via the fecal-oral route, with infection arising from ingestion of water or food contaminated with cysts. Individuals in low-resource settings, international travelers, outdoor enthusiasts, daycare...