Question

What happens to the neurotransmitters after a new action potential has fired?

Answer 1

Neuron's communication is carried out by chemical neurotransmitters controlled and by action potentials. The synapse cleft is the space between the pre-synaptic axon terminal and post-synaptic dendrite. Once an action potential is initiated the neurotransmitters are released by the original neuron which now can initiate an action potential in another neuron, or inhibit an action potential chain reaction or undergo destruction or diffusion. When then signal is strong enough on firing an action potential the neurotransmitters from the initiating neuron are released into the synaptic cleft and these bind to the neurotransmitters on the post-synaptic dendrites, and cause the opening of ion channels or voltage gated ion channels controlling the flux of Na+, K+, Ca+ or Cl-. And there by creates an electric pulse across the membrane. This eventually may result in depolarization or hyper polarization. This binding of the neurotransmitter to the post-synaptic dendrite is reversible, wherein post binding, the neurotransmitters have three types of fate, which are a) they may be taken up by a pre-synaptic axon terminal along with the action of acstrocytes and thereafter be enzymatically digested or can be stored for further use, b) Enzymes like acetylcholinesterases can degrade or destroy these neurotransmitters in the synaptic cleft and the the third fate C) is the neurotransmitter leaves the scene of action potential depolarization site by diffusion. These are the events that take place with the neurotransmitters after an action potential is fired.