G-protein gated ion channels are passageways in the cell membrane that allow the passage of a specific set of particles called G-proteins. Only this set of particles are allowed through this particular type of passageway. This is part of what defines the cell membrane's characteristic known as "selective permeability", meaning it will allow the passage of some particles or substances, while denying others. The G-protein gated ion channel is kind of like having to belong to a particular club; membership is required to gain admittance. G-proteins are particles that function largely in neurotransmitter functions for the cell, delivering appropriate responses for specific stimuli. G-protein gated ion channels are responsible for maintaining balance of G-proteins within the confines of the cell membrane, within the cell's interior.