Brain Tour :

About 60 substances are either known or suspected to be neurotransmitters. These substances establish the line of communication between nerve cells. When a neurotransmitter is described as inhibitory, it means that it prevents impulses from being passed from cell to cell. When it is excitatory, it literally excites the cells and impulses are passed.
Following are some examples of neurotransmitters: 1. Acetycholine. Found in cerebral cortex, all skeletal muscles and autonomic nervous system; usually excitatory.
2. Dopamine. Concentrated in the brain ; generally excitatory; involved in emotional responses and subconscious meovements of skeletal muscles ; decreased levels associated with Parkinson's disease.
3. Norephinephrine. Released at some muscle and gland nerve junctions; concentrated in the brain stem; also found in CNS; usually excitatory; may be related to arousal and mood.
4. Serotonin. Found in CNS , generally inhibitory; may be involved in sleep, sensory perception, temperature regulation, and control of mood.
5. Gamma aminobutyric acid (GABA). COncentrated in the brain; inhibitory; probably a target for antianxiety durgs such as valium, which enhances the action of Gamma aminobutyric acid.
6. Enkephalins. Concentrated in CNS. Inhibit pain impulses by supressing substances the cause pain.
7. Endorphins. Concentrated in pituitary glands and brain; inhibit pain and may have a role in memory and learning, sexual desire, control of body temperature and have been linked to depression and schizophrenia.