15.1.1 Mood Disorders 2 Flashcards
Blocking histamine produces _____. Blocking acetylcholine leads to ___ ____ and difficulty urinating. Blocking sodium channels causes ____ irregularities.
drowsiness : dry mouth : heart
The ____ ____ ____ ____ (SSRIs) are similar to tricyclics but specific to the neurotransmitter serotonin. For example, fluoxetine (trade name Prozac) blocks the reuptake of serotonin.
selective serotonin reuptake inhibitors
Several new drugs are serotonin ____ reuptake inhibitors (SNRIs).
norepinephrine
____ ____ ____ (MAOIs) (e.g., phenelzine, trade name Nardil) blocks the enzyme monoamine oxidase (MAO), a presynaptic terminal enzyme that metabolises catacholamines and serotonin into inactive forms.
Monoamine oxidase inhibitors
When MAOIs block this enzyme, the presynaptic terminal has more of its ____ available for release.
transmitter
People using MAOIs must avoid foods containing ____ – including cheese, raisins, and many others – because a combination of tyramine and MAOIs increases blood pressure.
tyramine
The ____ ____ are a miscellaneous group – everything other than the types just discussed. One example is bupropion which inhibits reuptake of dopamine and to some extent norepinephrine but not serotonin.
atypical antidepressants
In addition, many people use _______ for depression, an herb.
St John’s Wort
St John’s Warts effectiveness appears to be about the ____ as that of a standard antidepression drugs.
same
However, it has a potentially dangerous ____: all mammals have a liver enzyme that breaks down plant toxins. St John’s wort increases the effectiveness of that enzyme.
side-effect
Increasing the breakdown of toxins sounds like a good thing, but the enzyme also breaks down most ____. Therefore taking St John’s wort decreases the effectiveness of other drugs you might be taking.
medicines
The commonly used antidepressants increase the presence of serotonin and other ____ at the synapse, and so it might seem that the problem with depression is too little of the neurotransmitters.
neurotransmitters
However, the story is not that simple. So far as we can tell from blood metabolites, people with depression have approximately normal levels of release of ____.
neurotransmitters
Furthermore, it is possible to decrease serotonin levels suddenly. For most people, this decrease in serotonin does not ____ any feelings of depression.
provoke
Furthermore, given that different drugs act in different ways on different neurotransmitters, wouldn’t you expect some of them to be more effective than others? So far as we can tell, all of them are about equal in ____.
effectiveness
The ____ ____ of effects poses an additional threat to any explanation in terms of neurotransmitters: antidepression drugs produce their effects on neurotransmitters in the synapses within minutes to hours, depending on the drug, but people need to take a drug for two more weeks before they experience any mood elevation.
time course
This ____ of ____ strongly suggests that increasing the levels of neurotransmitters at synapses does not explain the benefits of the drugs.
delay of benefits
Today, much research attention focuses on ____. ____ aid in the survival, growth, and connections of neurons.
neurotrophins
Most people with depression have lower than average levels of a neurotrophin called ____ ____ ____ (BDNF) that is important for synaptic plasticity, learning, and proliferation of neurons in the hippocampus.
brain-derived neurotrophic factor
As a result of low BDNF, most people with depression have a smaller than average hippocampus, impaired learning, and reduced production of new ____ ____.
hippocampal neurons
Prolonged use of anti-depressant drugs generally increases BDNF production and improves learning and formation of new neurons. This process takes ____.
weeks
Apparently BDNF by itself does not automatically ____ ____, but it helps by facilitating new learning that builds new synapses and removes many old ones.
elevate mood
That mode of action by BDNF explains why antidepressants help people in depression – who might profit from substituting new thoughts for old ones – but failed to elevate mood for ____ ____.
normal people
In most cases, depression occurs in episodes. That is, even without treatment, many people recover within a few ____.
months
Furthermore, giving someone a medication produces an ____ of ____, thereby enhancing the probability of recovery, even if the medication itself is ineffective.
expectation of improvement
