Pharmacology Quiz #12: G-Protein-Linked Second Messengers

1. A 22-year-old woman is brought to the emergency department after ingesting a large quantity of mushrooms she found while hiking. She exhibits symptoms of excessive salivation, lacrimation, and bradycardia. The toxic substance in the mushrooms is likely an agonist at which of the following receptor types? 

Question 1 of 5

2. A pharmaceutical company is developing a new drug for the treatment of congestive heart failure. The drug is designed to increase the strength of cardiac muscle contractions. It achieves this by stimulating a receptor that activates adenylate cyclase, increasing cAMP levels within cardiac myocytes. This receptor is most likely coupled to which of the following G proteins? 

Question 2 of 5

3. A 45-year-old man with a history of hypertension is prescribed a new antihypertensive medication. This medication works by inhibiting a receptor that normally decreases cAMP levels in vascular smooth muscle cells, causing relaxation and vasodilation. The inhibited receptor is most likely coupled to which of the following G proteins? 

Question 3 of 5

4. A researcher is studying a cell line that lacks the Gq protein. When these cells are exposed to a specific ligand, there is no increase in intracellular calcium levels. Normally, this ligand binds to a receptor that activates phospholipase C (PLC). The absence of which of the following molecules is directly responsible for the observed lack of calcium increase? 

Question 4 of 5

5. During an experiment, a group of cells is treated with a drug that specifically inhibits Gi protein function. Following treatment, which of the following changes in second messenger levels is most likely to occur in these cells? 

Question 5 of 5


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