How does the activation of a Gi-beta/gamma complex affect K+ channels in a hyperpolarized cell?

How does the activation of a Gi-beta/gamma complex affect K+ channels in a hyperpolarized cell?

• A. It stimulates the opening of Na+ channels
• B. It stabilizes K+ channels
• C. It promotes the opening of K+ ion channels
• D. It inhibits K+ ion channels

Answer: (C)

In hyperpolarized cells, the activation of a Gi-beta/gamma complex promotes the opening of K+ ion channels. When a G protein coupled receptor (GPCR) is activated, the Gi protein dissociates into its alpha and beta/gamma subunits. The beta/gamma complex plays a crucial role in modulating various ion channels, particularly by influencing K+ channels, often referred to as muscarinic K+ channels or GIRK (G-protein-coupled inwardly rectifying K+) channels. When the Gi-beta/gamma complex binds to these K+ ion channels, it causes them to open, allowing an influx of K+ ions into the cell. This increase in intracellular K+ concentration further hyperpolarizes the cell, making it less likely to fire an action potential. The opening of K+ channels due to the activation of the Gi-beta/gamma complex is a key way in which cells can regulate their excitability and maintain their resting membrane potential. The option stating that it inhibits K+ channels is incorrect, as the activity of the Gi-beta/gamma complex actually facilitates K+ channel opening, which enhances hyperpolarization instead of inhibiting it. Other options regarding the effects on Na+ channels or stabilization of K

In hyperpolarized cells, the activation of a Gi-beta/gamma complex promotes the opening of K+ ion channels. When a G protein coupled receptor (GPCR) is activated, the Gi protein dissociates into its alpha and beta/gamma subunits. The beta/gamma complex plays a crucial role in modulating various ion channels, particularly by influencing K+ channels, often referred to as muscarinic K+ channels or GIRK (G-protein-coupled inwardly rectifying K+) channels.

When the Gi-beta/gamma complex binds to these K+ ion channels, it causes them to open, allowing an influx of K+ ions into the cell. This increase in intracellular K+ concentration further hyperpolarizes the cell, making it less likely to fire an action potential. The opening of K+ channels due to the activation of the Gi-beta/gamma complex is a key way in which cells can regulate their excitability and maintain their resting membrane potential.

The option stating that it inhibits K+ channels is incorrect, as the activity of the Gi-beta/gamma complex actually facilitates K+ channel opening, which enhances hyperpolarization instead of inhibiting it. Other options regarding the effects on Na+ channels or stabilization of K