Which substance acts primarily on the enzymes of the mitochondria of the brain?

Cyanide is a potent chemical that primarily targets the mitochondria's ability to utilize oxygen in the cellular respiration process, specifically inhibiting cytochrome c oxidase. This enzyme is crucial for the electron transport chain, where energy in the form of adenosine triphosphate (ATP) is generated. By blocking this enzyme, cyanide effectively prevents cells from using oxygen, leading to rapid cellular and brain damage due to energy depletion.

This is particularly critical in the context of the brain, which is highly dependent on aerobic respiration for its energy needs. Without oxygen, brain cells can suffer irreversible damage, leading to neurological dysfunction or death. Understanding this mechanism is essential when analyzing cases of poisoning or investigating potential sources of exposure to cyanide.