List the criteria that are used to determine whether a chemical serves as a neurotransmitter. What are the various experimental strategies you could use to show that ACh fulfills the criteria of a neurotransmitter at the neuromuscular junction?

Sourav PanSeptember 24, 2024

Answered

The criteria used to determine whether a chemical serves as a neurotransmitter are as follows:

1. Synthesis and Storage: The molecule must be synthesized and stored in the presynaptic neuron.
2. Release: The molecule must be released by the presynaptic axon terminal upon stimulation.
3. Mimicking Response: The molecule, when experimentally applied, must produce a response in the postsynaptic cell that mimics the response produced by the release of the naturally occurring neurotransmitter from the presynaptic neuron .

Experimental Strategies to Show ACh Fulfills the Criteria at the Neuromuscular Junction:

1. Localization:
   • Immunocytochemistry: This technique can be used to visualize the presence of ACh in the presynaptic terminals of motor neurons at the neuromuscular junction. Specific antibodies against ACh can be used to confirm its localization.
2. Release:
   • Electrophysiological Techniques: Use techniques such as voltage-clamp or patch-clamp recordings to measure the release of ACh in response to electrical stimulation of the motor neuron. The detection of ACh in the synaptic cleft can be confirmed by measuring the resulting postsynaptic potential in the muscle fiber.
3. Mimicking Response:
   • Direct Application: Apply ACh directly to the postsynaptic muscle cell and measure the resulting muscle contraction. This response should mimic the natural contraction that occurs when ACh is released from the presynaptic neuron during stimulation.

These strategies collectively help establish that ACh meets the criteria for being classified as a neurotransmitter at the neuromuscular junction.