This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: PHA 5515 April 29, 2006 Exam Form A Total: 122 points Read each question carefully before answering. Answer only the question that is written on the page; don’t add any of your own parts to it. By taking this exam, you agree to abide by the following policy: We, the members of the University of Florida community, pledge to hold our peers and ourselves to the highest standards of honesty and integrity. On my honor, I have neither given nor received unauthorized aid on this examination No calculators are needed. Please keep the test and turn in answer sheets when you have finished. Good Luck! True/False (2 pt) Sumatriptan (Imitrex®) and zolmitriptan (Zomig®) are some commonly used antimigraine drugs (Figure 1). Methysergide, ergotamine (Ergomax®) and LSD can have some antimigraine effects but may have side effects including hallucinations (Figure 2). You suspect that these efficacies are based on the ability of these drugs to bind to different subtypes of serotonin receptors. Therefore you compare the efficacies and potencies of these drugs to displace the specific binding of 3 H-serotonin from its receptors in homogenized brain samples (Figure 3). Zomig® can only bind to one third of the sites occupied by 3 H-serotonin (the 5HT1 receptor subtype) while LSD can only bind to the other two thirds of the receptors (the 5HT2 receptor subtype). Which of the following conclusions would be true? A = True, B = Not True 1. Methysergide and Ergomax® can bind to both 5HT1 and 5HT2 receptor subtype but the IC 50 values for the two subtypes are more alike for Ergomax® than they are for methysergide. 2. Imitrex® can not bind specifically to any 5HT receptor subtype at nanomolar concentrations. 3. Ergomax® clearly has a lower affinity for the 5HT1 receptor subtype compared to Zomig®’s affinity for the 5HT1 receptor subtype. 4. Ergomax® would be able to compete for at least a portion of specific binding if a competition curve were performed using 3 H-Zomig® as the radiolabeled drug. 5. Imitrex® would be able to compete for at least a portion of specific binding if a competition curve were performed using 3 H- LSD as the radiolabeled drug. 6. Methysergide clearly has a lower affinity for the 5HT1 receptor subtype compared to its affinity for the 5HT2 receptor subtype. 7. You would suspect that 66% of the serotonin receptors (5HT2 receptor subtype) are involved in the hallucinogenic effects of these drugs. 8. You would suspect that 34% of the serotonin receptors (5HT1 receptor subtype) are involved in the antimigraine effects of these drugs. 9. Methysergide is a partial agonist at the 5HT1 receptor subtype. 10. Methysergide is a partial agonist at the 5HT2 receptor subtype....
View Full Document
This note was uploaded on 04/27/2009 for the course CHM 2046 taught by Professor Veige/martin during the Spring '07 term at University of Florida.
- Spring '07