Which of the following neurotransmitters would most likely bind to ligand-gated ion channels?

Which of the following neurotransmitters would most likely bind to ligand-gated ion channels?

• A. Amino acids such as glutamate
• B. Peptides such as endorphins
• C. Monoamines such as dopamine
• D. Steroids such as cortisol

Answer: (A)

Ligand-gated ion channels are a specific type of membrane proteins that open in response to the binding of a neurotransmitter. This binding allows ions to flow through the channel, which can lead to changes in the membrane potential of a neuron and therefore influence signal transmission. Amino acids, such as glutamate, are well-known for serving as excitatory neurotransmitters in the central nervous system. When glutamate binds to its respective ligand-gated ion channel (such as the NMDA receptor or AMPA receptor), it opens the channel, allowing ions like sodium (Na+) or calcium (Ca2+) to enter the neuron. This influx of positively charged ions generates a depolarizing effect, making it more likely for the neuron to fire an action potential. In contrast, peptides like endorphins typically act through G protein-coupled receptors rather than directly influencing ion channels in the way that glutamate does. Similarly, monoamines such as dopamine primarily interact with G protein-coupled receptors as well, which can indirectly affect ion channels but do not operate through ligand-gated ion channels directly. Steroids such as cortisol, on the other hand, are lipophilic hormones that generally enter cells and act on intracellular receptors, altering gene

Ligand-gated ion channels are a specific type of membrane proteins that open in response to the binding of a neurotransmitter. This binding allows ions to flow through the channel, which can lead to changes in the membrane potential of a neuron and therefore influence signal transmission.

Amino acids, such as glutamate, are well-known for serving as excitatory neurotransmitters in the central nervous system. When glutamate binds to its respective ligand-gated ion channel (such as the NMDA receptor or AMPA receptor), it opens the channel, allowing ions like sodium (Na+) or calcium (Ca2+) to enter the neuron. This influx of positively charged ions generates a depolarizing effect, making it more likely for the neuron to fire an action potential.

In contrast, peptides like endorphins typically act through G protein-coupled receptors rather than directly influencing ion channels in the way that glutamate does. Similarly, monoamines such as dopamine primarily interact with G protein-coupled receptors as well, which can indirectly affect ion channels but do not operate through ligand-gated ion channels directly. Steroids such as cortisol, on the other hand, are lipophilic hormones that generally enter cells and act on intracellular receptors, altering gene