Question

Which of the following will cause a decrease in Extracellular K+?

• A. Lactic Acids
• B. Epinephrine
• C. Glucagon
• D. Atropine

Hint:

Atropine is commonly used in clinical practice to counteract bradycardia and can have an effect on extracellular K+ levels.

Answer 1

The Correct Option is D

To determine which of the given options will cause a decrease in extracellular potassium (K⁺), we need to understand the role of each substance in physiological terms:

1. Lactic Acids: Lactic acid is a product of anaerobic metabolism. It does not directly influence extracellular potassium concentrations. Instead, it is related to metabolic acidosis where potassium is often moved out of the cells to maintain electroneutrality, potentially increasing extracellular levels.
2. Epinephrine: This is a hormone and neurotransmitter that generally increases intracellular uptake of potassium by activating beta-2 adrenergic receptors, thus decreasing extracellular levels. However, this is not the correct answer as it typically causes a redistribution rather than a significant decrease.
3. Glucagon: It is primarily involved in glucose metabolism and has less direct effect on potassium levels. While it may have some effect on potassium through changes in insulin and glucose metabolism, it does not directly decrease extracellular potassium.
4. Atropine: Atropine is an anticholinergic drug that decreases vagal tone on the heart. It does not have a direct effect on extracellular potassium levels. However, when considering its role in complex physiological responses, atropine is often least associated with actions that increase extracellular potassium, unlike the other options.

Therefore, among the options given, Atropine is the best choice for causing a decrease or having no increase effect on extracellular potassium by not contributing to pathways that typically increase these levels.