[Campbell Biology P.1130] Which of the following statements about different classes of neurot... | Practice Question
Which of the following statements about different classes of neurotransmitters is accurate?
A: Serotonin and dopamine are amino acid neurotransmitters, with serotonin being made from tryptophan and dopamine from tyrosine.
B: Neuropeptides are relatively short chains of amino acids that can mediate our perception of pain (e.g., Substance P) or function as natural analgesics (e.g., endorphins).
C: Nitric oxide (N=O) is classified as a biogenic amine and serves as a gaseous neurotransmitter.
D: Norepinephrine is an inhibitory neurotransmitter primarily found in the central nervous system, where it regulates sleep and mood.
Explanation
The text states that 'Several neuropeptides, relatively short chains of amino acids, serve as neurotransmitters that operate via G protein-coupled receptors.' It also mentions 'The neuropeptide Substance P is a key excitatory neurotransmitter that mediates our perception of pain. Other neuropeptides, called endorphins, function as natural analgesics, decreasing pain perception.'