Chemistry of Synaptic Transmission Review

Comprehensive flashcards covering the chemistry of synaptic transmission, including neurotransmitter types, mechanisms of action for acetylcholine and glutamate, and the role of nitric oxide.

What is the name of the fibrous projection of a nerve cell that reaches toward the next neuron?

Axon

How is a nerve impulse defined in the context of neuronal transmission?

A wave of electrical charge sweeping from neuron to neuron

What is the term for the gap between one neuron and the next?

Synapse

What are the two alternative names for a neurotransmitter provided in the text?

Chemical transmitter or chemical messenger

What is the general function of neurotransmitters in the nervous system?

They are chemical agents released by neurons which result in the stimulation of neighbouring neurons or muscle or gland cells, allowing impulses to be passed from one cell to the next.

Where are neurotransmitters typically stored within the neuron?

In vesicles, typically located in the axon’s terminal end (presynaptic terminal)

What happens when a nerve impulse arrives at the presynaptic terminal?

Neurotransmitter molecules are released through the presynaptic membrane and into the synaptic cleft.

How long does it typically take for neurotransmitters to travel across the synaptic cleft?

Milliseconds

What is the primary effect of receptor activation on the second cell's membrane?

It causes either the opening or closing of membrane ion channels, altering the cell’s permeability.

In many instances, what does a change in cell permeability cause and what is the result?

It causes depolarization, which leads the cell to produce its own action potential and initiates an electrical impulse.

List three examples of amino acids that act as neurotransmitters.

Glutamate, glycine, and \text{̲} - \text{aminobutyric acid} (Gaba)

List three examples of amines used as neurotransmitters.

Dopamine, serotonin, and acetylcholine

Name four examples of peptide neurotransmitters listed in the notes.

Somatostatin, opioids, metenkephalin, and Tyr-Gly-Gly-Phe-Met

What is an example of a purine that acts as a neurotransmitter?

$$\text{ATP}$$

Which gaseous substance is identified as being able to act as a neurotransmitter?

Nitric oxide

What is the chemical formula for Glycine as shown in the transcript?

$$\text{+NH}_3\text{CH}_2\text{COO}^-$$

What is the chemical formula for \text{̲} - \text{aminobutyric acid} (Gaba)?

$$\text{+NH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{COO}^-$$

A deficiency of GABA is associated with which neurological disorder?

Huntington’s chorea

What are the common symptoms of Huntington’s chorea mentioned in the notes?

Speech disturbance, irregular movements, and mental deterioration

What is the chemical formula for Glutamate (Glu) provided in the lecture?

$$\text{CH}_2\text{CH}_2\text{COO}^- \text{+NH}_3\text{CHCOO}^-$$

How is the presynaptic neuron distinguished from the postsynaptic neuron?

The presynaptic neuron is before the synapse; the postsynaptic neuron is on the other side of the synapse.

What part of the nervous system does Acetylcholine primarily operate in to control autonomous organs?

The autonomic nervous system

What organs are mentioned as being controlled by the autonomic nervous system without conscious effort?

Heart and lungs

What is the main job of acetylcholine regarding nerve and muscle cells?

To carry a signal from nerve cells to muscle cells

What physical process is triggered when acetylcholine opens receptors on muscle cells?

Contraction

Name five cognitive or physiological roles played by Acetylcholine.

Memory, learning, attention, arousal, and involuntary muscle movement

Low levels of acetylcholine are associated with which condition?

Alzheimer’s Disease

What are the two chemical classifications for Acetylcholine according to its structure?

Quaternary amine and Ester

Which enzyme is responsible for hydrolyzing acetylcholine once its work is done?

Acetylcholinesterase

How does Botulism toxin from the botulinum bacterium affect a neuron?

It prevents a neuron from releasing acetylcholine.

What is the effect of nerve gases on the body's chemistry?

They deactivate acetylcholinesterase, causing the signal to continue until the heart fails.

Why is it essential that a neurotransmitter is destroyed after the message is passed?

Otherwise later signals would get mixed up in a jumble of obsolete neurotransmitter molecules.

What are the two precursors used in the synthesis of acetylcholine (ACh)?

Acetyl coenzyme A (ACoA) and choline

What are the five steps of the Acetylcholine lifecycle in order?

1. Synthesis from ACoA and choline; 2. Storage in pre-synaptic vesicles; 3. Release into synapse; 4. Binding/activation of receptors; 5. Inactivation by acetylcholinesterase (AChE).

Where is the enzyme acetylcholinesterase (AChE) located?

In the synapse

What are the products of the enzyme-catalysed hydrolysis of Acetylcholine?

Choline and Acetate

In the Nitric Oxide pathway, what happens when Glutamate interacts with its receptor?

It causes $\text{Ca}^{2+}$ ion channels to open.

In the Nitric Oxide pathway, what does calcium ($\text{Ca}^{2+}$) bind to after entering the cell?

Calmodulin

What enzyme is activated by the binding of calcium to calmodulin?

Nitric oxide synthase

Nitric oxide synthase converts arginine into which two products?

Nitric Oxide (NO) and citrulline

Why can Nitric Oxide (NO) diffuse to a huge number of neurons in the vicinity?

It is a small molecule that is soluble in both water and lipid.

Which enzyme does NO activate to cause vascular relaxation?

Guanylate cyclase

Why is Nitric Oxide (NO) considered a retrograde messenger?

Because it diffuses back to the pre-synaptic neuron and activates the release of glutamate.

What are the amino acid components of the peptide Metenkephalin?

Tyr-Gly-Gly-Phe-Met

What is the presynaptic terminal?

The terminal end of an axon where neurotransmitters are stored in vesicles.

What triggers the process of contraction in muscle cells?

The opening of receptors by acetylcholine.

What is the full name of the enzyme abbreviated as AChE?

Acetylcholinesterase

Under what general conditions can ester hydrolysis occur, as referenced in the lecture slides?

Acidic or Alkaline conditions

Who is the professor for the lecture 'Chemistry of Synaptic Transmission'?

Professor Celine Marmion

On what date was the lecture MNB.13 delivered?

29th October 2025