Niebramkowane kanały jonowe

Ion channels are transmembrane proteins that allow the passive movement of ions to maintain the electrochemical gradient across the membrane.

These channels can be gated or non-gated. The gated ion channels require a stimulus, such as a ligand, voltage change, or mechanical stress, for their opening. Whereas, non-gated ion channels need no such stimulus.

Non-gated ion channels, also known as leak or passive channels, open and close at random, allowing ions to pass through whenever they open.

These channels have narrow, highly selective pores lined by conserved amino acid residues that allow the diffusion of only specific ions.

The potassium leak channels present on the nerve cell membrane are a well-studied example of non-gated ion channels. As the name suggests, these channels allow excess potassium ions to diffuse out of the cell down the concentration gradient.

This efflux of positive ions plays an important role in maintaining a negative charge on the cytoplasmic side and a positive charge on the exoplasmic side of the membrane – a characteristic of nerve cells when not conducting impulses.