Which one of the following CNS receptors is directly coupled to an ion channel so that the effects of its activation do not involve second messenger systems?

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ATI Intro to Pharmacology Quizlet Questions

Question 1 of 5

Which one of the following CNS receptors is directly coupled to an ion channel so that the effects of its activation do not involve second messenger systems?

Correct Answer: A

Rationale: Nicotinic acetylcholine (N ACh) receptors are ligand-gated ion channels, directly opening to allow sodium and potassium flux upon acetylcholine binding, producing rapid effects without second messengers—key in neuromuscular transmission. Alpha-adrenergic (a NE) receptors couple to G-proteins, using second messengers like IP3 or cAMP. D2A dopamine receptors inhibit adenylate cyclase via Gi proteins, involving cAMP. Mu opioid receptors (µ) also use Gi proteins, reducing cAMP and opening potassium channels indirectly. 5HT2 serotonin receptors activate phospholipase C, generating IP3. The nicotinic receptor's direct ion channel linkage distinguishes it, enabling fast synaptic responses without the delay of intracellular signaling cascades.

Question 2 of 5

The nurse enters a patient’s room to find that his heart rate is 120, his blood pressure is 70/50, and he has red blotching of his face and neck. Vancomycin is running intravenous piggyback. The nurse believes that this patient is experiencing a severe adverse effect called red man syndrome. What action will the nurse take?

Correct Answer: A

Rationale: Red man syndrome is a hypersensitivity reaction to vancomycin, characterized by flushing, rash, hypotension, and tachycardia. The nurse should immediately stop the infusion to prevent further reaction and call the health care provider for further instructions. Reducing the infusion rate may help in mild cases, but in this severe case, stopping the infusion is the priority. Encouraging fluids is not appropriate for managing this acute reaction. Stevens-Johnson syndrome is a different, more severe condition and is not indicated by these symptoms.

Question 3 of 5

When administering the anticoagulant drug Warfarin, what is one of the two lab tests you should monitor to distinguish the effectiveness of the drug?

Correct Answer: B

Rationale: When administering the anticoagulant drug Warfarin, one of the two lab tests you should monitor to distinguish the effectiveness of the drug is the International Normalized Ratio (INR). INR measures the time it takes for blood to clot and is used to monitor the effects of Warfarin therapy. The target INR range for patients on Warfarin therapy varies depending on the indication for treatment, but in general, a higher INR indicates that the blood is taking longer to clot, which means the Warfarin is working effectively to prevent blood clots. Regular monitoring of the INR levels is essential to ensure that patients are receiving an appropriate dose of Warfarin to prevent both clotting and bleeding complications.

Question 4 of 5

A 24-year-old man is admitted for an emergent appendectomy. While in the operating room, the anesthesiologist finds that he must use a much higher than expected anesthetic dose to anesthetize this patient. After the surgery, the patient admits to barbiturate abuse. What is the correct term for the fact that his history of barbiturate abuse led to a greater anesthetic requirement?

Correct Answer: C

Rationale: Barbiturate abuse increases anesthetic need due to cross-tolerance . Chronic use induces enzymes and receptor changes, reducing anesthetic efficacy. Addiction , dependence , and cross-dependence don't explain dosing. Tolerance (E) is drug-specific. Cross-tolerance fits this scenario.

Question 5 of 5

A patient taking SMZ/TMP asks the nurse what the name means. The nurse replies sulfamethoxazole is combined with trimethoprim in SMZ/TMP to help the drug effectiveness. How does this work?

Correct Answer: D

Rationale: SMZ/TMP (sulfamethoxazole/trimethoprim) works synergistically to inhibit bacterial folate synthesis at two different steps, making it effective against a broad spectrum of gram-positive and gram-negative organisms. It does not act as an anesthetic (A), displace trimethoprim (B), or increase excretion in the bladder (C). The combination enhances antibacterial activity and reduces the risk of resistance.

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