A patient is admitted to the emergency department with signs and symptoms that could be due to either a muscarinic stimulant or an opioid. Which of the following is a common effect of both muscarinic stimulant drugs and opioids?
(A) Decreased peristalsis
(B) Decreased secretion by salivary glands
(D) Inhibition of thermoregulatory sweat glands
E (7, 31) Neither opioids nor muscarinic agonists decrease salivation, decrease sweating, or raise blood pressure. Opioids decrease peristalsis; muscarinics increase it*. Both drug groups can cause miosis.
Which statement about prostacyclin is most correct?
(A) Prostacyclin is synthesized in mitochondria of the brain
(B) Prostacyclin causes uterine contractions
(C) Prostacyclin synthesis is stimulated by NSAIDs
(D) Prostacyclin synthase is inhibited by histamine
(E) Prostacyclin causes pulmonary vasodilation
E (18) Prostacyclin (PGI2) is not synthesized in mitochondria, it is derived from arachidonic acid, which is released from cell membrane lipids by phospholipase A. Cyclooxygenase generates prostaglandins, including prostacyclin, from arachidonic acid endoperoxide derivatives in the cytosol. PGE2 and PGF2α, not PGI2, cause uterine contraction. PGI2 synthesis is reduced by NSAIDs, not by histamine.
A 35-year-old patient is brought to the emergency department in a drug-induced coma. Blood samples taken over the next several hours show a declining drug concentration, as shown in the graph below. Which of the following drugs is the most likely cause of this patient’s coma?
B (1) The graph shows first-order elimination of the drug in question (note ordinate is a log scale). Aspirin, ethanol, and phenytoin are eliminated mainly by zero-order kinetics. Diazepam is the only drug in the list that is eliminated by first-order kinetics.
In a laboratory study of a new agent, the activity of a membrane-bound enzyme was found to be decreased by the drug. Analysis of this enzyme molecule revealed that it is a part of a membrane transporter. Which of the following receptors combine enzyme activity with a transport function?