Which one of the following statements regarding drug effects on serotonin receptor systems is accurate?
5HT2 receptor blockers counteract bronchoconstriction and diarrhea of carcinoid. Sumatriptan is an antiemetic because it blocks 5HT3 receptors. MAO type B inhibitors lead to increased levels of serotonin in the CNS. Ondansetron is used in migraine because it activates 5HT1D receptors.