Question 1

Another name for serotonin is
A) 5-hydroxytryptophan.
B) tryptophan.
C) 5-hydroxytryptamine.
D) tryptamine.

Accepted Answer

Serotonin is scientifically known as 5-hydroxytryptamine, which reflects its chemical structure.

Question 2

What type of meal is most likely to increase brain levels of serotonin in animals?
A) High carbohydrate, high protein
B) High carbohydrate, low protein
C) Low carbohydrate, low protein
D) Low carbohydrate, high protein

Accepted Answer

High carbohydrate, low protein meals are most likely to increase brain levels of serotonin in animals. This is because carbohydrates can increase the level of tryptophan in the brain, which is a precursor to serotonin. Protein-rich foods, on the other hand, contain amino acids that compete with tryptophan for entry into the brain, potentially reducing its effect on serotonin synthesis.

Question 3

Why might increasing levels of tryptophan in the blood not increase brain serotonin levels?
A) It doesn't matter how much tryptophan is present, serotonin is made at a constant rate from brain stores of tryptophan.
B) Tryptophan cannot cross the blood-brain barrier under any circumstances.
C) Tryptophan competes with other amino acids for transport across the blood-brain barrier.
D) Insulin is required for transport of tryptophan across the blood-brain barrier.

Accepted Answer

Tryptophan competes with other amino acids for transport across the blood-brain barrier, so increased levels in the blood do not necessarily lead to increased brain serotonin levels.

Question 4

Researchers study the effects of serotonin depletion in human subjects by
A) using the synthesis blocking drug PCPA.
B) administering a special milkshake that is rich in tryptophan hydroxylase.
C) injecting subjects with insulin to alter the ratio of amino acids in the blood.
D) administering a cocktail of amino acids that compete with tryptophan for entry into the brain.

Accepted Answer

Administering a cocktail of amino acids that compete with tryptophan for entry into the brain is a method used to deplete serotonin levels by reducing the availability of tryptophan, the precursor to serotonin.

Question 5

One potential consequence of administration of an amino acid cocktail to human subjects is that
A) depressed subjects may experience a total remission of depressive symptoms if given a tryptophan-free cocktail.
B) serotonin syndrome can result.
C) previously healthy subjects can develop depression and anxiety if given a tryptophan-containing cocktail.
D) previously depressed but currently recovered patients maintained on a 5-HT-based antidepressant developed symptoms of depression if given a tryptophan-free cocktail.

Accepted Answer

Tryptophan is a precursor to serotonin, and a tryptophan-free cocktail can lower serotonin levels, potentially leading to a return of depressive symptoms in patients who rely on serotonin-based antidepressants.

Question 6

All of the following can increase the presence of serotonin in the synaptic cleft except
A) DOI.
B) MDMA.
C) fenfluramine.
D) fluoxetine.

Accepted Answer

DOI (2,5-dimethoxy-4-iodoamphetamine) is a psychedelic drug that primarily acts as a serotonin receptor agonist, rather than increasing the presence of serotonin in the synaptic cleft. MDMA, fenfluramine, and fluoxetine all increase serotonin levels in the synaptic cleft through various mechanisms.

Question 7

The activity of serotonergic neurons in humans can be determined indirectly by measuring
A) levels of 5-HIAA in cerebrospinal fluid.
B) levels of 5-HIAA in blood.
C) levels of 5-HT in cerebrospinal fluid.
D) activation of SERT.

Accepted Answer

Levels of 5-HIAA (5-hydroxyindoleacetic acid) in cerebrospinal fluid are a common indirect measure of serotonergic neuron activity because 5-HIAA is a major metabolite of serotonin (5-HT).

Question 8

Later generation drugs used to treat schizophrenia, such as clozapine and risperidone, block/activate _______ receptors and produce _______ motor side effects. A) D₂; severe B) 5-HT_2A; fewer C) 5-HT_2A; severe D) both D₂ and 5-HT_2A; severe

Accepted Answer

Later generation antipsychotics, such as clozapine and risperidone, primarily block 5-HT2A serotonin receptors and are known for producing fewer motor side effects compared to first-generation antipsychotics.

Question 9

5,7-Dihydroxytryptamine (5,7-DHT)
A) is a metabolite of serotonin.
B) destroys the cell bodies of the serotonergic neurons.
C) inhibits serotonin synthesis.
D) must be administered directly into the brain.

Accepted Answer

5,7-Dihydroxytryptamine (5,7-DHT) is a neurotoxin that selectively destroys serotonergic neurons and is typically administered directly into the brain to avoid peripheral effects and to ensure it reaches the target neurons.

Question 10

Which method(s) can be used to produce mice that lack brain serotonin throughout life, beginning with embryonic development?
A) Administering the tryptophan hydroxylase inhibitor PCPA
B) Knocking out the gene for tryptophan hydroxylase 2
C) Preventing the normal differentiation of cells that are destined to become serotonergic neurons
D) Both b and c

Accepted Answer

Methods B and C directly target the genetic or developmental processes responsible for serotonin production. Knocking out the gene for tryptophan hydroxylase 2 (B) eliminates the enzyme necessary for serotonin synthesis, ensuring mice lack brain serotonin from development. Preventing the differentiation of serotonergic neurons (C) stops these cells from producing serotonin throughout the mouse's life.

Question 11

In mice with a knockout of the tryptophan hydroxylase 2 gene,
A) no serotonin can be synthesized in any part of the animal's body.
B) no pharmacological treatment has been found that is able to restore serotonin, even temporarily.
C) the circuitry of the serotonergic system (fiber innervation) is normal, despite the lack of serotonin.
D) impulsive aggression is increased compared to wild-type mice.

Accepted Answer

Impulsive aggression is increased in mice with a knockout of the tryptophan hydroxylase 2 gene, which is required for serotonin synthesis.

Question 12

One brain region implicated in the neural circuitry of aggression in rodents but not in humans is the
A) amygdala.
B) cingulate cortex.
C) BNST.
D) hypothalamus.

Accepted Answer

The Bed Nucleus of the Stria Terminalis (BNST) is specifically implicated in the neural circuitry of aggression in rodents but has not been shown to play the same role in humans.

Question 13

Evidence supporting a link between low levels of 5-HT and/or receptor activation and increased aggression, or high levels of 5-HT and/or receptor activation and decreased aggression, comes from all of the following studies except for those
A) measuring 5-HT release during play of violent video games.
B) correlating 5-HIAA concentration in the cerebrospinal fluid and measures of aggressive behavior.
C) using SSRIs to increase extracellular 5-HT levels.
D) examining inhibition of tryptophan hydroxylase.

Accepted Answer

Studies measuring 5-HT release during the play of violent video games do not directly support the link between 5-HT levels/receptor activation and aggression. The other options (B, C, D) involve direct measurements or manipulations of serotonin (5-HT) system components and their correlation with aggression, making them relevant to the question.

Question 14

Evidence that serotonergic abnormalities may be involved in sudden infant death syndrome (SIDS) comes from studies showing that A) the incidence of SIDS decreases if infants are given SSRIs. B) response to a CO₂ challenge in mutant mice lacking central serotonin can be improved by treatment with DOI. C) apnea in mutant mice lacking central serotonin can be reversed with SSRIs. D) infants who died of SIDS had a reduced number of 5-HT_2A receptors in their brain.

Accepted Answer

The answer of Evidence that serotonergic abnormalities may be involved...

Question 15

Administration of _______ is not likely to lead to a decrease in food intake and thus weight loss. A) 5-HT_1B agonists B) 5-HT_2C agonists C) 5-HT_1A agonists D) 5-HT₆ antagonists

Accepted Answer

5-HT_1A agonists are not typically associated with reducing food intake or promoting weight loss, unlike 5-HT_1B and 5-HT_2C agonists, and 5-HT₆ antagonists, which can influence appetite and weight.

Question 16

Which statement regarding serotonin and anxiety is false? A) Buspirone is an effective antianxiety medication and a partial agonist at 5-HT_1A receptors. B) Knockout mice lacking 5-HT_1A receptors show increased anxiety on the elevated zero maze. C) Knockout mice lacking 5-HT_2A receptors show decreased anxiety-like behaviors. D) The 5-HT_2A/2C receptor agonist mCPP is an effective antianxiety medication.

Accepted Answer

The statement D is false because mCPP (meta-Chlorophenylpiperazine), a 5-HT2C receptor agonist, is not used as an antianxiety medication; in fact, it can induce anxiety and panic attacks in humans.

Question 17

Studies using animal models have shown that serotonin is involved in _______ pain.
A) cancer-related
B) neuropathic
C) hypoalgesia
D) electric shock-induced

Accepted Answer

Serotonin is involved in modulating neuropathic pain, which is pain caused by damage or disease affecting the somatosensory nervous system.

Question 18

Administration of a 5-HT₄ receptor partial agonist A) impairs memory consolidation in a 1-trial fear conditioning task. B) improves cognitive function in patients with Alzheimer's disease. C) enhances learning and memory in various learning tasks in rodents and monkeys. D) affects cognitive function by inhibiting cholinergic transmission in the neocortex and hippocampus.

Accepted Answer

Administration of a 5-HT₄ receptor partial agonist enhances learning and memory in various learning tasks in both rodents and monkeys, as it positively influences the serotonergic system which plays a significant role in cognitive processes.

Question 19

The 5-HT₆ antagonist ________ is being tested as a potential therapeutic agent to improve cognitive function in patients with Alzheimer's disease. A) idalopirdine B) donepezil C) vilazodone D) lorcaserin

Accepted Answer

Idalopirdine is a 5-HT6 antagonist being tested as a potential therapeutic agent to improve cognitive function in patients with Alzheimer's disease.

Question 20

Describe the synthesis of serotonin and explain why serotonin levels in the brain can be increased by consumption of a high-carbohydrate, low-protein meal.

Accepted Answer

The answer of Describe the synthesis of serotonin and explain...

Quiz 5: Serotonin

Another name for serotonin is

What type of meal is most likely to increase brain levels of serotonin in animals?

Why might increasing levels of tryptophan in the blood not increase brain serotonin levels?

Researchers study the effects of serotonin depletion in human subjects by

One potential consequence of administration of an amino acid cocktail to human subjects is that

All of the following can increase the presence of serotonin in the synaptic cleft except

The activity of serotonergic neurons in humans can be determined indirectly by measuring

Later generation drugs used to treat schizophrenia, such as clozapine and risperidone, block/activate _ receptors and produce _ motor side effects.

5,7-Dihydroxytryptamine (5,7-DHT)

Which method(s) can be used to produce mice that lack brain serotonin throughout life, beginning with embryonic development?

In mice with a knockout of the tryptophan hydroxylase 2 gene,

One brain region implicated in the neural circuitry of aggression in rodents but not in humans is the

Evidence supporting a link between low levels of 5-HT and/or receptor activation and increased aggression, or high levels of 5-HT and/or receptor activation and decreased aggression, comes from all of the following studies except for those

Evidence that serotonergic abnormalities may be involved in sudden infant death syndrome (SIDS) comes from studies showing that

Administration of _______ is not likely to lead to a decrease in food intake and thus weight loss.

Which statement regarding serotonin and anxiety is false?

Studies using animal models have shown that serotonin is involved in _______ pain.

Administration of a 5-HT₄ receptor partial agonist

The 5-HT₆ antagonist ________ is being tested as a potential therapeutic agent to improve cognitive function in patients with Alzheimer's disease.

Describe the synthesis of serotonin and explain why serotonin levels in the brain can be increased by consumption of a high-carbohydrate, low-protein meal.

Quiz 5: Serotonin

Another name for serotonin is

What type of meal is most likely to increase brain levels of serotonin in animals?

Why might increasing levels of tryptophan in the blood not increase brain serotonin levels?

Researchers study the effects of serotonin depletion in human subjects by

One potential consequence of administration of an amino acid cocktail to human subjects is that

All of the following can increase the presence of serotonin in the synaptic cleft except

The activity of serotonergic neurons in humans can be determined indirectly by measuring

Later generation drugs used to treat schizophrenia, such as clozapine and risperidone, block/activate _______ receptors and produce _______ motor side effects.

5,7-Dihydroxytryptamine (5,7-DHT)

Which method(s) can be used to produce mice that lack brain serotonin throughout life, beginning with embryonic development?

In mice with a knockout of the tryptophan hydroxylase 2 gene,

One brain region implicated in the neural circuitry of aggression in rodents but not in humans is the

Evidence supporting a link between low levels of 5-HT and/or receptor activation and increased aggression, or high levels of 5-HT and/or receptor activation and decreased aggression, comes from all of the following studies except for those

Evidence that serotonergic abnormalities may be involved in sudden infant death syndrome (SIDS) comes from studies showing that

Administration of _______ is not likely to lead to a decrease in food intake and thus weight loss.

Which statement regarding serotonin and anxiety is false?

Studies using animal models have shown that serotonin is involved in _______ pain.

Administration of a 5-HT4 receptor partial agonist

The 5-HT6 antagonist ________ is being tested as a potential therapeutic agent to improve cognitive function in patients with Alzheimer's disease.

Describe the synthesis of serotonin and explain why serotonin levels in the brain can be increased by consumption of a high-carbohydrate, low-protein meal.

Later generation drugs used to treat schizophrenia, such as clozapine and risperidone, block/activate _ receptors and produce _ motor side effects.

Administration of a 5-HT₄ receptor partial agonist

The 5-HT₆ antagonist ________ is being tested as a potential therapeutic agent to improve cognitive function in patients with Alzheimer's disease.