[Mediators. Evolution of the concept].

Area of Science:

• Neuroscience
• Biochemistry

Background:

• Chemical mediators are crucial for intercellular communication in the central and peripheral nervous systems.
• The precise definition of a neurotransmitter or mediator remains debated among scientists.
• Historical context reveals evolving criteria for classifying neurochemical messengers.

Purpose of the Study:

• To provide an up-to-date overview of chemical mediators in the nervous system.
• To discuss the contemporary classification of these signaling molecules.
• To highlight recently identified classes of mediators.

Main Methods:

• Literature review of scientific and historical data.
• Analysis of the evolving definition of chemical mediators.
• Synthesis of current classifications of neurochemical agents.

Main Results:

• The definition of a chemical mediator has shifted with the discovery of new substances.
• A contemporary classification categorizes mediators into diverse chemical groups.
• Gases and D-amino acids are now recognized as potential mediators.

Conclusions:

• Understanding chemical mediators is essential for comprehending neural signaling.
• The classification of mediators is dynamic, reflecting ongoing research.
• Expanding the definition includes novel compounds like gaseous transmitters and D-amino acids.