Which neurotransmitter is excitatory and associated with excitotoxicity when present in excess?

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Multiple Choice

Which neurotransmitter is excitatory and associated with excitotoxicity when present in excess?

Glutamate is the primary excitatory neurotransmitter in the central nervous system, and when it is present in excess it can drive excitotoxicity. This happens when overactivation of glutamate receptors, especially NMDA receptors, causes a large influx of calcium into neurons. The resulting calcium overload activates a cascade of destructive processes—calcium-activated enzymes, generation of reactive oxygen species, mitochondrial dysfunction, and membrane and DNA damage—that lead to neuronal injury and death. GABA and glycine are mainly inhibitory, reducing neuronal excitability, while acetylcholine can be excitatory in some contexts but is not the classic trigger for excitotoxic damage. Therefore, glutamate best fits the pattern of being excitatory and linked to excitotoxic injury when in excess.

Glutamate is the primary excitatory neurotransmitter in the central nervous system, and when it is present in excess it can drive excitotoxicity. This happens when overactivation of glutamate receptors, especially NMDA receptors, causes a large influx of calcium into neurons. The resulting calcium overload activates a cascade of destructive processes—calcium-activated enzymes, generation of reactive oxygen species, mitochondrial dysfunction, and membrane and DNA damage—that lead to neuronal injury and death.

GABA and glycine are mainly inhibitory, reducing neuronal excitability, while acetylcholine can be excitatory in some contexts but is not the classic trigger for excitotoxic damage. Therefore, glutamate best fits the pattern of being excitatory and linked to excitotoxic injury when in excess.

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