Which of the following is NOT a neurotransmitter associated with chemotherapy induced nausea and vomiting?

The reasoning behind the selection of GABA as the correct answer lies in the role that neurotransmitters play in the neurobiology of chemotherapy-induced nausea and vomiting (CINV). Dopamine, serotonin, and substance P are well-established neurotransmitters involved in the pathways that mediate nausea and vomiting, particularly in the context of chemotherapy.

Serotonin, especially, has been shown to play a critical role as it is released from enterochromaffin cells in the gut in response to chemotherapy agents and acts on 5-HT3 receptors in the chemoreceptor trigger zone, leading to nausea and vomiting.

Dopamine is also involved through its receptors in the brain, which are targeted by certain antiemetic drugs to help control nausea. Substance P interacts with neurokinin-1 receptors and is another key player in the signaling pathways that are triggered during chemotherapy.

In contrast, GABA (gamma-aminobutyric acid) is primarily known as an inhibitory neurotransmitter responsible for reducing neuronal excitability throughout the nervous system. While it plays a significant role in many functions, including anxiety and mood regulation, it is not directly associated with the mechanisms of nausea and vomiting instigated by chemotherapy. Therefore, its absence in the context of C