What are the receptors in the brain

Receptors are the key

In Germany there are around one million epileptics and around 250,000 people with Parkinson's disease. While the first group of patients suffers from irregular seizures, in which control over the body is lost, people with Parkinson's disease are usually noticeable through their movement and facial expressions, for example through a creeping gait, the trembling of the hands and fingers or because of their mask-like face . But where do these symptoms come from?

Information transfer in the brain © FZ Jülich

"In the brain of Parkinson's disease sufferers, epileptics or stroke patients, the transmitter receptors behave differently than in healthy people," says Professor Karl Zilles, head of the Institute for Medicine (IME) at Forschungszentrum Jülich. Transmitter receptors are crucial for the transmission of information in the brain - without them, nerve cells would not be able to “talk” to one another. Scientists from the IME and the Institute for Nuclear Chemistry (NC) are investigating the complex relationships in which the various types of receptors in the brains of healthy and sick people are involved.

Transmitter receptors are protein molecules in the membrane of the nerve cells. (Neurons). Messenger substances - so-called neurotransmitters - can couple to them. The messengers were previously released by another nerve cell at special contact points, the synapses, in order to transmit a message. When docking with the receptor, it becomes active: It can then, for example, open an ion channel through which electrically charged particles flow into the neuron. This changes the electrical charge distribution between the inside of the cell and its surroundings: the nerve cell is “excited”. If the excitation is strong enough, the cell in turn releases messenger substances. It forwards the message to other cells before it "calms down" again.

Some transmitter receptors work in a different way: They intervene in the nerve cell's metabolism or activate parts of the cell's own genetic information. For example, transmitter receptors can influence the growth of a neuron or help it to adapt to special functional requirements. Receptors are “specialists”: “A receptor only ever accepts one of many different types of transmitters. Conversely, however, a messenger substance can bind to different types and subtypes of receptors, ”explains Prof. Zilles.

This is the reason for an astonishing observation: one and the same messenger substance can have a stimulating effect in one case and inhibitory in the other by binding to different receptors. The brain researchers are familiar with seven classic, chemically relatively simple and fast-acting neurotransmitters in the human central nervous system. There are also more than 20 more complex messenger substances, the neuropeptides. On the other hand, there are many different types of transmitter receptors - and certainly not all of them have been discovered yet.

The situation is further complicated by the fact that the same receptors and transmitters can exert different effects in different brain areas that are often only a few millimeters apart: For example, the same receptor can have a stimulating or inhibiting effect on movements in motor brain regions, in regions that are important for memory are important, but affect the ability to remember.

Status: March 16, 2001

March 16, 2001