Uncle mel suffers from depression and is having trouble sleeping. some medications can increase the amount of neurotransmitter in the synapse by preventing its re-uptake into the presynaptic neuron and its degradation. this increases the level of the neurotransmitter in the synapse and prolongs its effects. select which neurotransmitters you think might be a good target for anti-depressant drugs.

Targets for anti-depressant drugs: serotonin (also norepinephrine and / or dopamine)

Explanation:

   Depression is the presence of depressive mood or loss of interest or pleasure for at least two weeks, in addition to a series of other related symptoms such as psychomotor and sleep disorders, reduced concentration, variation in body weight and loss of energy.  

   For over decades, the biological basis of depressive disorders has been explained through the monoaminergic hypothesis of depression. This theory proposes that depression is a consequence of the lower availability of brain biogenic amines, in particular serotonin, norepinephrine and / or dopamine. This proposition is reinforced by the knowledge of the mechanism of action of antidepressants, which is based mainly on the increased availability of these neurotransmitters in the synaptic cleft, either by inhibiting (selective or not) their reuptake, or by inhibiting the enzyme responsible for their degradation (monoaminoxidase inhibitors) .

   The serotonin is most known as the main cause of depression. The idea that low levels of serotonin in certain areas of the brain would be the cause of depression was reinforced by the demonstration that the emergence of drugs capable of increasing brain neurotransmitter concentrations of serotonin (like fluoxetine and sertraline) could help people with this disorder.

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enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products