29 Questions
What is the enzyme responsible for catalyzing the conversion of L-Histidine into histamine?
L-Histidine Decarboxylase
Which amino acid precursor is required for the biosynthesis of histamine?
L-Histidine
What is the final metabolite produced when methylation occurs during the degradation of histamine?
Methyl imidazole acetic acid
Which drug induces the release of histamine and is derived from plants?
Reserpine
Where does the oxidation of methylated histamine directly occur in its metabolism?
Diamine Oxidase
Which enzyme adds a methyl group to the structure of histamine during its degradation process?
N-methyl transferase
What is the main second messenger pathway associated with histamine H1 receptors?
IP3 & DAG signaling
Which histamine receptor subtype is primarily responsible for bronchoconstriction in the airways?
H1 receptor
What is the main effect of histamine H1 receptor activation on endothelial cells in capillaries?
Vascular leakage and edema
What response commonly occurs during anaphylaxis due to increased histamine concentration?
Hypotension
Which signaling molecules are released from endothelial cells upon activation of histamine H1 receptors in blood vessels?
Nitric oxide & Prostaglandin I
What is the main compensatory mechanism triggered by the body in response to a decrease in blood pressure due to histamine H1 receptor activation?
Reflex Tachycardia
Which second-generation antihistamine is considered a derivative of cetirizine?
Levocetirizine
Which antihistamine is recommended for customers with occupations like drivers and pilots due to its non-sedating effect?
Loratadine (Claritin)
Which antihistamine is known as the active metabolite of loratadine?
Desloratadine
Which antihistamine is primarily used for individuals who need a non-sedating effect, such as pilots and drivers?
Fexofenadine (Allegra)
Which first-generation antihistamine is considered the drug of choice for acute dystonia or dystonia crisis?
Diphenhydramine
What is the specialized process that serotonin undergoes when it is formed?
Vesicular storage process
Where is the majority of serotonin synthesized in the body?
Platelets
What allows the transport of biogenic monoamines like serotonin into vesicles?
Vesicular Monoamine Transporter (VMAT)
What triggers the movement of stored forms of serotonin in vesicles?
Entry of Ca2+ via Voltage-gated Calcium Ion channels
What is one possible fate of serotonin in the synaptic cleft?
Enhanced serotonergic effect
Why must neurotransmitters synthesized in the presynapse be stored in vesicles?
To prevent premature metabolism
What is the primary use of Ergotamine?
Prophylaxis of Migraine
Which medication is NOT a vaso-selective agent?
Methysergide
What is the first-line management for Postpartum Hemorrhage?
Oxytocin
Which medication is a 5-HT3 antagonist?
Granisetron
What is a severe side effect associated with Methysergide?
Retroperitoneal Fibrosis
Which medication is legally used in Europe as an anti-hypertensive agent?
Ketanserin
This quiz covers the pharmacology of antihistamines, drugs that prevent the effects of histamine, along with substances that induce histamine release such as certain plant-derived drugs. It also delves into the biosynthesis and metabolism of histamine with a focus on the amino acid precursor L-Histidine.
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