The Role Of Neurotransmitters In The Body

What Are Neurotransmitters? by Jane Thurnell-Read

Neurotransmitters are small molecules that transmit information across the junction that separates one nerve cell (neuron) from:

Another nerve cell or

A muscle cell or

A glandular cell

Neurotransmitters include serotonin, acetylcholine, dopamine and GABA. Some neurotransmitters (e.g. noradrenaline) also function as hormones. Most neurons use only one compound as their neurotransmitter.

Neurotransmitters are manufactured from compounds such as amino acids, glucose and choline, e.g. serotonin is derived from the amino acid tryptophan, GABA is made from glucose, and acetylcholine has choline as its precursor (raw material).

The site where neurons meet is called the synapse and consists of:

• The axon terminal (transmitting end) of one cell.
• The dendrite (receiving end) of the next.
• An infinitesimal microscopic gap (the synaptic cleft) between the neurons.

Molecules of neurotransmitters are stored in small "packages" called vesicles. When an electrical impulse travelling along a nerve reaches the axon, the vesicle fuses with the membrane of the axon terminal, spilling the neurotransmitter into the synaptic cleft. The neurotransmitter travels across the synapse. When enough of the neurotransmitter has made this journey, it either prompts or inhibits the electrical impulses along the new nerve. This allows impulses to be passed from one cell to the next throughout the nervous system.

Some neurotransmitters can be both excitatory and inhibitory, e.g. acetylcholine is excitatory at nerve/muscle junctions, but can be excitatory or inhibitory at nerve/nerve junctions.

A similar process happens if the post-synaptic cell is a muscle cell or a glandular cell rather than a neuron. An excitatory neurotransmitter will cause the muscle to contract or the cell to secrete its contents. An inhibitory neurotransmitter will damp down the activity of the muscle or secreting cell.

Once they have had the desired effect the neurotransmitters are cleared by:

Being broken down by enzymes (e.g. acetylcholine is broken down by acetylcholinesterase to choline and acetate, neither of which have neurotransmitter activity).

or

Being reabsorbed into the neuron of origin, where they are broken down by enzymes or re-used (e.g. dopamine, serotonin, GABA). Some drugs work as re-uptake inhibitors, e.g. some anti-depressants, so that the neurotransmitter is present for longer.

There are several neurotransmitters in Body Biochemicals test kit 1 and 2. (These are suitable for use by kinesiologists and EAV practitioners)

Enjoyed this article? Then look at the one on the related topics of neuropeptides and prostaglandins.