Post by Diane on Mar 10, 2004 16:09:06 GMT -5
Neurotransmitters: How They Work
A neurotransmitter is a chemical that transmits information across nerve synapses. A synapse is the end of a nerve, which, when stimulated, will touch another nerve ending while releasing vesicles (little containers) filled with neurotransmitters. When the neurotransmitter reaches the receptor (receiving end) of another nerve, it causes a biological effect, such as increased heart rate or constriction of the blood vessels. After the chemical has been released, it must be deactivated through reuptake (reabsorbtion by the nerve that released it in the first place) or the release of an enzyme that changes the structure of the chemical so it is no longer recognized by the receptor (deactivation or degradation).
For a great illustrations and explanations of how nerves transmit signals to each other, go to Dr. Chudler's "Neuroscience for Kids"
Serotonin
Serotonin (5-hydrozytryptamine or 5-HT) receptors are divided into 7 classes. These classes have 10 subtypes. In essence, there are 17 types of serotonin receptors found all over your body. Each receptor causes different biological effects, hence the creation by drug companies of selective serotonin reuptake inhibitors. Each SSRI blocks a different type, or group, of serotonin receptors from reabsorbing the chemical serotonin. Prozac works on all 17 types of receptors. Because serotonin affects so many body systems, the possibility for experiencing side effects when taking an SSRI is high, particularly in the stomach and intestines.
Among other things, serotonin affects blood clotting, heart beat, sleep, fighting depression, migraine headaches (because it can cause blood vessels to constrict or spasm), and also stimulates release of a hormone that regulates that body clock.
Serotonin (5-HT) Receptors
Class
Subtypes
5-HT1
5-HT1A
5-HT1B
5-HT1C
5-HT1D
5-HT1E
5-HT1F
5-HT2
5-HT2A
5-HT2B
5-HT2C
5-HT3
5-HT4
5-HT5
5-HT5A
5-HT5B
5-HT6
5-HT7
Different Serotonin Receptors and Their Effects:
5-HT1A: Controls mood.
5-HT1B: Controls release of other neurotransmitters, such as dopamine; has analgesic (pain relief) and anti-depressant properties. Laboratory studies show that mice lacking the 5-HT1B receptor show more aggression and an increase in desire for alcohol.
5-HT1D: Possibly an autoreceptor for 5-HT (receives only 5-HT).
5-HT1E: Function is not known.
5-HT1F: May be linked to migraine headaches.5-HT2A: Controls contraction in vascular, urinary, gastrointestinal, and uterine functions. Drugs that block this receptor may improve sleep quality.
5-HT2B: Reduces anxiety, agitation, or tension. May be linked to migraines. Found in the brain, placenta, lung, liver, kidney, heart, intestine, and stomach.
5-HT2C: May regulate production of cerebral spinal fluid. May affect penile erection and sleep. Laboratory studies show that mice lacking the 5-HT2C receptor suffer from convulsions, obesity, and cognitive impairment (difficulty in thinking/learning).
5-HT3: Affects cardiac function, induces dilation of blood vessels, affects the lungs and intestines, may cause nausea and vomiting in response to pain.
5-HT4: Associated with dopamine function. Affects colon and bladder contraction, and bodily secretions. May induce tachycardia (rapid heart rate). Possibly linked to controlling anxiety. 5-HT5: Function is not known.
5-HT6: Perhaps stimulates yawning and stretching?
5-HT7: Affects relaxation of smooth muscle tissue.
OTHER NEUROTRANSMITTERS
Dopamine
Dopamine plays several different roles in the brain. It modulates brain activity (keeping us stable), controls movement, regulates the flow of information to other areas of the brain. Dopamine is thought to release chemicals that allow us to feel pleasure. A lack of dopamine in the brain can produce Parkinson's Disease or schizophrenia. All of the functions of dopamine are not yet known.
Norepinephrine (noradrenaline)
Norepinephrine is a neurotransmitter found in the sympathetic nervous system (in the thoracic and lumbar regions of the spinal cord). The sympathetic nervous system stimulates the heart, blood vessels, sweat glands, the large interior organs, and the adrenal medulla in the brain. Norepinephrine causes physiological expressions of fear and anxiety. People with anxiety disorders have been found to have an excess of norepinephrine.
www.depressiondepot.net/Medications/neurotransmitters.html
A neurotransmitter is a chemical that transmits information across nerve synapses. A synapse is the end of a nerve, which, when stimulated, will touch another nerve ending while releasing vesicles (little containers) filled with neurotransmitters. When the neurotransmitter reaches the receptor (receiving end) of another nerve, it causes a biological effect, such as increased heart rate or constriction of the blood vessels. After the chemical has been released, it must be deactivated through reuptake (reabsorbtion by the nerve that released it in the first place) or the release of an enzyme that changes the structure of the chemical so it is no longer recognized by the receptor (deactivation or degradation).
For a great illustrations and explanations of how nerves transmit signals to each other, go to Dr. Chudler's "Neuroscience for Kids"
Serotonin
Serotonin (5-hydrozytryptamine or 5-HT) receptors are divided into 7 classes. These classes have 10 subtypes. In essence, there are 17 types of serotonin receptors found all over your body. Each receptor causes different biological effects, hence the creation by drug companies of selective serotonin reuptake inhibitors. Each SSRI blocks a different type, or group, of serotonin receptors from reabsorbing the chemical serotonin. Prozac works on all 17 types of receptors. Because serotonin affects so many body systems, the possibility for experiencing side effects when taking an SSRI is high, particularly in the stomach and intestines.
Among other things, serotonin affects blood clotting, heart beat, sleep, fighting depression, migraine headaches (because it can cause blood vessels to constrict or spasm), and also stimulates release of a hormone that regulates that body clock.
Serotonin (5-HT) Receptors
Class
Subtypes
5-HT1
5-HT1A
5-HT1B
5-HT1C
5-HT1D
5-HT1E
5-HT1F
5-HT2
5-HT2A
5-HT2B
5-HT2C
5-HT3
5-HT4
5-HT5
5-HT5A
5-HT5B
5-HT6
5-HT7
Different Serotonin Receptors and Their Effects:
5-HT1A: Controls mood.
5-HT1B: Controls release of other neurotransmitters, such as dopamine; has analgesic (pain relief) and anti-depressant properties. Laboratory studies show that mice lacking the 5-HT1B receptor show more aggression and an increase in desire for alcohol.
5-HT1D: Possibly an autoreceptor for 5-HT (receives only 5-HT).
5-HT1E: Function is not known.
5-HT1F: May be linked to migraine headaches.5-HT2A: Controls contraction in vascular, urinary, gastrointestinal, and uterine functions. Drugs that block this receptor may improve sleep quality.
5-HT2B: Reduces anxiety, agitation, or tension. May be linked to migraines. Found in the brain, placenta, lung, liver, kidney, heart, intestine, and stomach.
5-HT2C: May regulate production of cerebral spinal fluid. May affect penile erection and sleep. Laboratory studies show that mice lacking the 5-HT2C receptor suffer from convulsions, obesity, and cognitive impairment (difficulty in thinking/learning).
5-HT3: Affects cardiac function, induces dilation of blood vessels, affects the lungs and intestines, may cause nausea and vomiting in response to pain.
5-HT4: Associated with dopamine function. Affects colon and bladder contraction, and bodily secretions. May induce tachycardia (rapid heart rate). Possibly linked to controlling anxiety. 5-HT5: Function is not known.
5-HT6: Perhaps stimulates yawning and stretching?
5-HT7: Affects relaxation of smooth muscle tissue.
OTHER NEUROTRANSMITTERS
Dopamine
Dopamine plays several different roles in the brain. It modulates brain activity (keeping us stable), controls movement, regulates the flow of information to other areas of the brain. Dopamine is thought to release chemicals that allow us to feel pleasure. A lack of dopamine in the brain can produce Parkinson's Disease or schizophrenia. All of the functions of dopamine are not yet known.
Norepinephrine (noradrenaline)
Norepinephrine is a neurotransmitter found in the sympathetic nervous system (in the thoracic and lumbar regions of the spinal cord). The sympathetic nervous system stimulates the heart, blood vessels, sweat glands, the large interior organs, and the adrenal medulla in the brain. Norepinephrine causes physiological expressions of fear and anxiety. People with anxiety disorders have been found to have an excess of norepinephrine.
www.depressiondepot.net/Medications/neurotransmitters.html