A Type of Drug-Food Interaction 3
October 2nd 2009 06:43
Neurotransmitter Synthesis, Transmission, and Degradation
Patient was advised by her doctor to take iproniazid, a MAO inhibitor. The drug then was new and no side effects of the drug have been documented.
But why was she advised to take such drug? In clinical practice MAO inhibitors are powerful antidepressants that are used as last line of defense, when other classes of anti-depressants have failed. The agent-from its own classification- inhibits an enzyme, monoamine oxidase, that degrades the neurotransmitters discussed earlier.
Before proceeding further with the drug action, it is essential that we discuss how neurotransmitters are synthesized, released from the terminal of each neuron, how they cause an effect to neighboring neurons, and how are they inhibited.
As we know it, neurotransmitters are responsible for relaying impulses or action potential from a neuron (presynaptic terminal) to another neuron or effector organs (postsynaptic structure). Such impulse relay is important in the communication of each part of the nervous system and effector organs, in order to maintain purposeful body processes.
The monoamine neurotransmitters are synthesized within the neurons before being stored in the presynaptic vesicles.
After release from the presynaptic terminals, the neurotransmitters are accepted by specific receptors in the post-synaptic membranes. Such binding of the neurotransmitter and receptor causes signal transduction and generation of action potential to effector tissue or organ.
Neurotransmitters must be broken down once it reaches the post-synaptic cell to prevent further excitatory or inhibitory signal transduction. They undergo reuptake and degraded by the enzymes, like monoamine oxidase(MAO). MAO-A is specific for serotonin and norepinephrine. MAO-B is specific for dopamine. Monoamine oxidases catalyze the oxidative deamination of monoamines. Oxygen is used to remove an amine group from a molecule, resulting in the corresponding aldehyde and ammonia.
Patient was advised by her doctor to take iproniazid, a MAO inhibitor. The drug then was new and no side effects of the drug have been documented.
But why was she advised to take such drug? In clinical practice MAO inhibitors are powerful antidepressants that are used as last line of defense, when other classes of anti-depressants have failed. The agent-from its own classification- inhibits an enzyme, monoamine oxidase, that degrades the neurotransmitters discussed earlier.
Before proceeding further with the drug action, it is essential that we discuss how neurotransmitters are synthesized, released from the terminal of each neuron, how they cause an effect to neighboring neurons, and how are they inhibited.
As we know it, neurotransmitters are responsible for relaying impulses or action potential from a neuron (presynaptic terminal) to another neuron or effector organs (postsynaptic structure). Such impulse relay is important in the communication of each part of the nervous system and effector organs, in order to maintain purposeful body processes.
The monoamine neurotransmitters are synthesized within the neurons before being stored in the presynaptic vesicles.
After release from the presynaptic terminals, the neurotransmitters are accepted by specific receptors in the post-synaptic membranes. Such binding of the neurotransmitter and receptor causes signal transduction and generation of action potential to effector tissue or organ.
Neurotransmitters must be broken down once it reaches the post-synaptic cell to prevent further excitatory or inhibitory signal transduction. They undergo reuptake and degraded by the enzymes, like monoamine oxidase(MAO). MAO-A is specific for serotonin and norepinephrine. MAO-B is specific for dopamine. Monoamine oxidases catalyze the oxidative deamination of monoamines. Oxygen is used to remove an amine group from a molecule, resulting in the corresponding aldehyde and ammonia.
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