While nerve cells may be the “building blocks” of the brain, how they communicate with each other determines our behavior. Nerve cells, or neurons, “talk” with each other by sending out chemicals called neurotransmitters. Acting as messengers, these neurotransmitters carry important messages from cell to cell. Nerve cells don’t actually touch each other, but instead are separated by a “gap” called a synapse. Within each nerve cell are tiny packets of neurotransmitters that when released, bridge the gap and carry a message to a neighboring cell, called the target cell. The neurotransmitters create changes in the target cell that transform it from being a target cell to a cell that is now ready to send the message it received to yet another cell.

A target cell must receive messages from numerous cells simultaneously before it is induced to change. This is how information is transferred throughout the nervous system.

To communicate with a nerve cell, neurotransmitters must first interact with a receptor. The receptor is like a “padlock” on the surface of the cell, while the neurotransmitter functions like a “key.” When the key engages the lock, one of two scenarios occurs. A door opens into the cell that allows ions to flow in, thereby increasing or reducing the electrical charge on the cell’s membrane. An increase in the charge inhibits the cell from generating an electrical impulse, while a decrease in the charge causes the cell to create an impulse. The electrical impulse travels down the cell’s axon, a sort of telephone wire with nerve endings at its end point. Once they receive the electrical impulse, the nerve endings are prompted to release the tiny packages of neurotransmitters that have been stored in the nerve endings up until this point. The neurotransmitters are released into the synapse, where they find their way to a neighboring cell. This chain reaction is the very basis of how the peripheral and central nervous systems function.

At UT-Houston, scientists are studying how neurotransmitters are made, how the packets of neurotransmitters are induced to release their contents, and how the receptors on the target cells go about changing the permeability of cell membranes. Some researchers study how commonly abused drugs interact with neurotransmitters, while others examine how neurotransmitters and their interaction with nerve cells could lead to the encoding of memory. Still others study the role of neurotransmitters in the decline of nervous system function when nerve cells are injured through stroke, trauma or epilepsy.