All body cells are able to display a membrane potential that is defined as the separation of positive and negative charges of a membrane that promotes the distribution of different chemicals (Sherwood, 2011). Communication is one of the main functions of the cells in the nervous system that is possible across synapses. The process of communication has several stages, and the evaluation of the ways of how neurons communicate to each other is a crucial step to be taken.
The beginning of communication is observed when one neuron receives a certain signal from another neutron at synapses (the process of neurotransmission). Neurotransmitters can influence the conditions of the postsynaptic membrane and promote the changes of the membrane in a result of a number of events connected with ion channels closing and opening regularly. This process is called an action potential. During it, the membrane potential depolarizes fast so that the inner membrane surface becomes more positive in comparison to the outer membrane surface. Then, the reversed process is observed, and the membrane comes back to resting potential.
In the communication process under consideration and during an action potential, in particular, the role of ions and ion channels cannot be neglected. Ions are the particles with positive charges (e.g. the sodium ions) and negative charges. Ion channels make the regular flow of ions in and out the cells possible via various electrostatic forces and diffusion processes. As soon as the movement of ions takes place through the channels, the charge changes promote the development of changes in the membrane, and the neural communication continues until a point of no return is achieved, and action potential (the generation of a large electrical signal) may be converted into a chemical signal.
This process is called a chemical synapse and represented by neurotransmitter release when the action potential arrives at synaptic knobs. It begins with an action potential reaching the nerve terminal. There are the synaptic vesicles that are combined with the plasma membrane. As soon as the transmitter reaches the synaptic cleft that is 20-40 nm long, it should get ready to pass it through. This kind of arrival requires the activation of a new voltage-gated cation channel (Ca2+) in the plasma membrane and its penetration in the terminal.
The concentration of this cation in the terminal leads to the combination of the synaptic vesicles and the plasma membrane and the development of a new process during which an electrical signal is converted into a chemical signal at that terminal. Then, the neuron continues traveling through ion channels that can span the membrane. However, this traveling is impossible in case a chemical signal is failed to be successfully received by the postsynaptic neuron.
When the neurotransmitter passes through the cleft, it binds to transmitter-gated ion channels. The released neurotransmitter molecules can bind to particular receptors that can be found on the postsynaptic neuron and promote a response only in case it has the right chemical shape. In case the molecules do not correspond with the requirements, they cannot bind to the receptor and cause the required response. Therefore, the interaction between the receptor and neurotransmitter happens in a lock-and-key way.
The result of this interaction is the return to a synaptic space. Those molecules that do not fit each other are degraded by enzymes and taken back in the presynaptic axon terminal (Sherwood, 2011). It is the way of how neurons may communicate to each other.
Reference
Sherwood, L. (2011). Fundamentals of human physiology. Belmont, CA: Cengage Learning.