The book "In Search of Memory" describes nerve cells or neurons that represent the basic signaling components in the brain. A synapse is the space between two nerve cells. Chemicals called neurotransmitters leave one nerve cell at the synapse space and communicate to the next neuron. The neurotransmitters turn on the electric impulse in the next nerve cell.
Neurotransmitters and Mood
"Integrative Psychiatry" describes four neurotransmitters that affect mood. The neurotransmitters of serotonin, norepinephrine, dopamine and GABA influence feelings in human beings. These chemicals function at the synapse space to turn on neurons for altering feelings in individuals. Serotonin and GABA, inhibitory neurotransmitters, slow the transmissions. Norepinephrine and dopamine, which are excitatory neurotransmitters, allows signals to go forward or increase the speed of the transaction.
Brain Areas and Mood
According to All About Self Help, the area of the brain regulating emotion involves the limbic system. The limbic system in the brain encompasses the hypothalamus, the amygdala and the hippocampus. The hypothalamus regulates the function of the pituitary gland that controls key hormones. The regions in the brain communicate with each other via the neurons and the neurotransmitter system.
Neurotransmitters and Depression
According to "Integrative Psychiatry," imbalances of the neurotransmitters of serotonin, norepinephrine, dopamine and GABA occur in depression. Neurotransmitter chemicals appear decreased in depression. The alterations in depression disrupt the communication between the brain and the body. The disruptions of communication produces the symptoms exhibited in depression.
Brain Areas and Depression
The National Institute of Mental Health reports that magnetic resonance imaging or MRI show brains of people with depression exhibit different images of the brain than people without depression. The parts of the brain responsible for regulating mood appear to function abnormally in depression. Therefore, depressive illness is a disorder of the brain as well.
Drug Actions in Depression
The newer antidepressants work to normalize the amount of neurotransmitters that affect mood. The selective serotonin reuptake inhibitors or SSRIs include drugs such as Celexa, Prozac and Zoloft. The SSRIs treat the depression with their effect on the neurotransmitter, serotonin. A class of drugs similar to SSRIs is the serotonin and norepinephrine reuptake inhibitors or SNRIs. The SNRI encompass the drugs, Effexor and Cymbalta, and act on the neurotransmitter, norepinephrine.
The older antidepressants function by reducing the breakdown of serotonin, norepinephrine and dopamine. The monoamine oxidase inhibitors or MAOIs include drugs like moclobemide and selegline. Because MAOIs produce a potentially lethal dietary and drug interaction, physicians reserve these drugs as a last line of defense and use this class of drug when other antidepressants fail.
References
- "In Search of Memory"; One Cell at a Time; E. R. Kandel, M.D.; 2006
- Integrative Psychiatry: The Four Major Neurotransmitters
- University of Washington: Neuroscience For Kids
- National Institute of Mental Health: Depression
- All About Depression: Biological Causes of Depression
