In bromethalin toxicity, decreased ATP production leads to which cellular consequence?

• A. Intracellular edema
• B. Increased ATP production
• C. Decreased glycolysis only
• D. No cellular effect

Answer: (A)

Bromethalin acts as a mitochondrial uncoupler, reducing ATP production in neurons. When ATP is scarce, energy-dependent ion pumps, especially the Na+/K+ ATPase, fail to maintain ion gradients. Sodium and water accumulate inside cells, causing cellular swelling known as intracellular or cytotoxic edema. This is the key consequence of energy failure in bromethalin toxicity, particularly in the brain where the demand for ATP is high.

The other options don’t fit because ATP production does not increase in this scenario, so increased ATP production is incorrect. The idea of decreased glycolysis only doesn’t reflect the typical response; glycolysis is usually upregulated as a compensatory mechanism to try to meet energy needs, not selectively decreased. Finally, there is a cellular effect—ATP depletion leads to edema—so no cellular effect is not correct.