The actions of some neurotransmitters are terminated by simple diffusion of the chemical back into the pre-synaptic terminal.

The actions of some neurotransmitters are terminated by binding of the chemical to G proteins in the pre-synaptic terminal.

The actions of all neurotransmitters are terminated by re-uptake of the chemical into glial cells.

The actions of all neurotransmitters are terminated by degradation by enzymes within the synaptic cleft.

The actions of some neurotransmitters are terminated by re-uptake of the chemical into the terminal.