A patient presented with progressive cognitive decline, an emerging personality disorder, and chorea. He was diagnosed with a neurodegenerative disorder, and his chorea was treated with phenothiazines. A CT scan showed atrophy of the head of the caudate nucleus. Which neurotransmitter is primarily involved in this disorder?

Correct Answer: C

Rationale: The correct answer is C) GABA. In the context of the presented case, the patient's symptoms of progressive cognitive decline, personality disorder, chorea, and atrophy of the caudate nucleus point towards Huntington's disease, a neurodegenerative disorder characterized by a reduction in GABAergic inhibition. GABA (gamma-aminobutyric acid) is the major inhibitory neurotransmitter in the brain and is particularly important in regulating movement and cognitive functions. In Huntington's disease, there is a loss of GABAergic neurons in the caudate nucleus, leading to the symptoms described. Option A) 5-hydroxytryptamine (serotonin) is not primarily involved in this disorder. While serotonin dysfunction can contribute to mood disorders, it is not the main neurotransmitter affected in Huntington's disease. Option B) Acetylcholine is not primarily involved in this disorder. Acetylcholine plays a role in motor control and cognitive function, but its dysfunction is not the primary cause of symptoms seen in Huntington's disease. Option D) Norepinephrine is not primarily involved in this disorder. Norepinephrine is involved in the body's stress response and mood regulation, but it is not the neurotransmitter primarily affected in Huntington's disease. Understanding the role of neurotransmitters in neurodegenerative disorders is crucial for healthcare professionals to accurately diagnose and manage patients with such conditions. This question provides a valuable learning opportunity to reinforce the relationship between neurotransmitter dysfunction and specific clinical manifestations seen in neurodegenerative diseases.

Correct Answer: B

Rationale: The correct answer is B) increased concentration of the blocked neurotransmitter in the synaptic gap. Explanation: Neurotransmitter inhibitors that block reuptake prevent the reabsorption of neurotransmitters back into the presynaptic neuron after they have been released into the synaptic gap. This results in an increased concentration of the blocked neurotransmitter in the synaptic gap. By blocking reuptake, these medications allow the neurotransmitter to remain in the synaptic gap longer, increasing its availability to bind to postsynaptic receptors and exert its effects. Why the other options are wrong: A) decreased concentration of the blocked neurotransmitter in the central nervous system: This is incorrect because blocking reuptake actually leads to an increased concentration of the neurotransmitter in the synaptic gap, not a decreased concentration in the central nervous system. C) destruction of receptor sites specific to the blocked neurotransmitter: This is incorrect because neurotransmitter inhibitors that block reuptake do not destroy receptor sites. They primarily act by interfering with the reuptake process, not by destroying receptors. D) limbic system stimulation: This is incorrect as it is not directly related to the mechanism of action of neurotransmitter inhibitors that block reuptake. These medications work by modulating neurotransmitter levels in the synaptic gap, rather than specifically targeting the limbic system for stimulation. Educational context: Understanding the mechanism of action of psychotropic medications is crucial for healthcare professionals working in mental health settings. Knowledge of how neurotransmitter inhibitors that block reuptake function can help in explaining the therapeutic effects and potential side effects of these medications to patients. It also aids in making informed decisions regarding medication selection and monitoring for adverse reactions.

Correct Answer: A

Rationale: The correct answer is A) SSRI (Selective Serotonin Reuptake Inhibitor). Paroxetine belongs to the class of SSRIs, which work by increasing the levels of serotonin in the brain. This class of medications is commonly used to treat depression and anxiety disorders, with a different side effect profile compared to tricyclic antidepressants like Tofranil (imipramine). Option B) Selective norepinephrine reuptake inhibitor is incorrect as it refers to a different class of antidepressants that primarily target norepinephrine reuptake, not serotonin like paroxetine. Option C) Tricyclic antidepressant is incorrect as Tofranil (imipramine) belongs to this class, which has different mechanisms of action and side effect profiles compared to SSRIs like paroxetine. Option D) MAO inhibitor is incorrect as it represents yet another class of antidepressants that inhibit the enzyme monoamine oxidase, again with different mechanisms and side effects compared to SSRIs. Educationally, it is crucial for healthcare professionals to understand the classes of psychotropic medications, their mechanisms of action, and common side effect profiles to make informed decisions in clinical practice. This knowledge helps in ensuring safe and effective medication management for patients with mental health conditions.

Correct Answer: B

Rationale: In this scenario, the correct answer is option B) Orthostatic hypotension. When a drug blocks the attachment of norepinephrine to α receptors, it leads to a decrease in the normal vasoconstrictor response that norepinephrine would typically initiate. This results in a reduced ability to maintain blood pressure when changing positions, causing orthostatic hypotension. Option A) Hypertensive crisis is incorrect because blocking norepinephrine attachment would not lead to increased blood pressure. In fact, it would have the opposite effect. Option C) Severe appetite disturbance is unrelated to the action of blocking norepinephrine at α receptors. This side effect is more commonly associated with other classes of psychotropic medications. Option D) Increase in psychotic symptoms is also incorrect as blocking norepinephrine attachment would not directly impact psychotic symptoms. This effect is more related to changes in dopamine and serotonin levels in the brain. Educationally, understanding the pharmacological mechanisms of psychotropic medications is crucial for healthcare professionals to predict and manage potential side effects. By comprehending how drugs interact with neurotransmitter systems, practitioners can make informed decisions when prescribing and monitoring patients on psychotropic medications. This knowledge enhances patient safety and treatment effectiveness.

Correct Answer: C

Rationale: In this question, the correct answer is C) Methadone. Methadone is a synthetic form of opium that was indeed developed by Germany during WWII. Methadone is commonly used today as a medication for managing opioid withdrawal symptoms and as a long-acting pain reliever. It works by binding to the same opioid receptors in the brain that drugs like heroin and morphine bind to, but it does so in a way that helps to reduce withdrawal symptoms and cravings without producing the same euphoric effects. Now, let's discuss why the other options are incorrect: A) Prednisalone and B) Cortisone are both types of corticosteroids, which are not synthetic forms of opium. Corticosteroids are mainly used for their anti-inflammatory properties and have different mechanisms of action compared to opioids like methadone. D) Polyheroin is not a known synthetic form of opium. The term "polyheroin" is not recognized in pharmacology or medicine. Educational context: Understanding the development and uses of different psychotropic medications, including synthetic opioids like methadone, is crucial for healthcare professionals working in fields like addiction medicine, psychiatry, and pain management. Knowing the properties and mechanisms of action of these medications helps in making informed decisions when prescribing and managing patients with substance use disorders or chronic pain.