Which chemical messengers are responsible for relaying information between neurons?

Neurotransmitters are specialized chemical messengers that play a crucial role in communication between neurons. When an electrical impulse, or action potential, travels down a neuron and reaches the end of the neuron (the axon terminal), it triggers the release of neurotransmitters from vesicles stored within the terminal. These neurotransmitters are then released into the synaptic cleft, the small gap between the sending neuron and the receiving neuron.

Once released, neurotransmitters bind to specific receptors on the surface of the receiving neuron, leading to various responses that can either excite or inhibit that neuron. This process allows neurons to process and transmit information rapidly, forming the basis for all neural communication, including reflexes, thoughts, and emotions.

In contrast, hormones are chemical messengers that travel through the bloodstream to target various organs and tissues, and while they also play important roles in signaling, they do not facilitate direct communication between neurons like neurotransmitters do. Enzymes are biological catalysts that speed up chemical reactions but are not involved in communication between neurons. Receptors, while crucial for receiving neurotransmitter signals, are not messengers themselves; instead, they are the target structures that respond to the neurotransmitters.