Depolarizáló

Depolarizáló is a term used in neurobiology and electrophysiology to describe a process that reduces or eliminates the membrane potential of a cell. This potential, often referred to as the resting potential, is the electrical charge difference across the cell membrane when it is not actively stimulated. In neurons, for example, this resting potential is typically negative on the inside relative to the outside.

Depolarization occurs when positively charged ions, such as sodium (Na+) or calcium (Ca2+), flow into the cell, making the inside of the membrane less negative or even positive. This influx of positive charge makes the cell more excitable. If the depolarization reaches a certain threshold, it can trigger an action potential, a rapid and transient change in membrane potential that is crucial for nerve impulse transmission.

Various stimuli can cause depolarization. In neurons, these include neurotransmitters binding to receptors, mechanical pressure, or changes in the extracellular environment. Ion channels in the cell membrane are responsible for controlling the flow of ions. When these channels open, allowing positive ions to enter, the cell depolarizes. Conversely, repolarization occurs when the membrane potential returns to its resting state, often due to the outflow of positive ions like potassium (K+). Hyperpolarization is a process where the membrane potential becomes more negative than the resting potential, making the cell less excitable.